Thursday, August 23, 2007

I have a Yamabuki Ogon. How can I tell how old he is? -Beka

Unless you were told by the breeder or the dealer, it is almost impossible to guess the age of your Koi. All Koi grow at different rates, most 2-6 inches a year. Over a few year period, some Koi will be a lot bigger than others.

Koi have growth rings in their scales, not unlike the rings in tree trunks. These rings can be counted with a microscope, although this method is sometimes inaccurate.

Monday, July 30, 2007

Keep Heron Away From Pond

How do I keep Heron from eating my Koi? The Heron decoy did not work. Will I always have to use a net over my pond? -Peggi

The best way to keep a Heron out of your pond is to build it with steep walls. Herons like to wade through shallow water and they have a hard time getting into a pond with a steep pitch. Many people also have a dog in their yard to chase them away.

Can koi fish live in a salty water?

Koi are a freshwater fish. They can live with a small amount of salt in the water. The only time that they need salt is for parasite control or for a thicker slime coat (salt will irritate a Koi's skin, making it produce a thicker slime coat).

When do Koi start to breed?

How old do the Koi have to be before they spawn....or breed? We've had ours for a little over a month and we now have a minimum of 17 babies....we have three 5-6" koi and two 4" koi.... -Tonya

Koi start to breed when they are usually 2 years old and over a foot long.

I bought a lot of Japanese Koi for 1 year but they haven't born any babies. Why? How can I do to get fish babies? -Ei Ei Khine

Are you sure that they are old enough to even breed yet? Koi usually start breeding when they are at least 2 years old and over 1 foot long. The urge to spawn is usually triggered in the spring, with the rising temperature of the water. They also need a place to spawn, usually a thicket of plant material.

PH Level Dropping

Since the weather has turned cold here in Perth Australia over the last month my PH level has dropped continually down from 7 to around 5.5 - 5. I have adjusted it with Bi-Carb soda to bring it back up at a rate of about 1.5 Tsp per 1000 litres but then a week later it will have dropped again. All my other water levels are spot on. Can you tell me why this is happening as during the summer months it was OK. Is Bi-Carb soda the correct way to raise the levels? What can you suggest to maintain a steady level of PH? Thank you, look forward to your suggestions. -William

I would do a water change and I would do it regularly. All your Koi are doing right now when they are hibernating is breathing. They breath in oxygen and exhale carbon dioxide. Carbon dioxide is acidic and will slowly eat away at carbonate levels in the water. As the carbonate levels go down, the water's ability to buffer acid also drops. That is why you pH keeps dropping. Doing a regular water change or adding Bi-Carb soda will keep the carbonate levels in your pond up.

I have algae floating in my pond. Is there anything I can do besides getting a UV Light? -Anthony

A UV light is usually used for taking care of the algae that turned the water green. In order for a UV light to kill algae, it needs to go through it. UV lights don't usually take care of floating algae. To get rid of the algae that floats in your pond, you can:
  • scoop it out by hand
  • do a large water change, on a regular basis
  • feed your fish less often (less food, less waste, less algae)
  • treat the pond with an algaecide or another algae killing chemical (not really good, algaecides can harm fish if not dosed right)

Do Koi mate with goldfish? Is it possible for my goldfish to spawn twice in two weeks? -Lynn

Koi will breed with goldfish. Usually the offspring look half goldfish/half Koi, with muddy colors. I'm not sure how often goldfish will breed, here's the wikipedia article on it:

Goldfish, like all cyprinids, lay eggs. They produce adhesive eggs that attach to aquatic vegetation. The eggs hatch within 48 to 72 hours, releasing fry large enough to be described as appearing like "an eyelash with two eyeballs". Within a week or so, the fry begin to look more like a goldfish in shape, although it can take as much as a year before they develop a mature goldfish color; until then they are a metallic brown like their wild ancestors. In their first weeks of existence, the fry grow remarkably fast - an adaptation born of the high risk of getting devoured by the adult goldfish (or other fish and insects) in their environment.

Goldfish can only grow to sexual maturity if given enough water and the right nutrition. However if kept well, they may breed indoors. Breeding usually happens after a significant change in temperature, often in spring. Eggs should then be separated into another tank, as the parents will likely eat any of their young that they happen upon. Dense plants such as Cabomba or Elodea or a spawning mop are used to catch the eggs.

Most goldfish can and will breed if left to themselves, particularly in pond settings. Males chase the females around, bumping and nudging them in order to prompt the females to release her eggs, which the males then fertilize. Due to the strange shapes of some extreme modern bred goldfish, certain types can no longer breed among themselves. In these cases, a method of artificial breeding is used called "hand stripping". This method keeps the breed going, but can be dangerous and harmful to the fish if not done correctly.

How can Koi be tamed to hand feeding? Is it just feeding at a particular time or are there attractant foods? -Arthut

Getting Koi to be hand tame takes time. First, get your Koi used to your presence. This can be achieved by first standing at the edge of your pond while you feed them. Then put your hand in the water and hold some food in it. Hold some food in you hand while it's in the water every day and eventually your Koi will get used to their food being in your hand. They will then eat from it.

Tuesday, July 17, 2007

Koi and Other Fish

Can a freshwater shark and fighter fish co-exist and breed with carp fish in a large pond? How about adding turtles to the collection? -Adam

Carp and Koi are docile. That means they won't harm any fish. Those other types of fish, including the turtle, are aggressive. That means they will tear apart any other type of fish in the pond. They carp will be lucky if they last a day. I would not mix any of those fish together.

Freshwater Snails

Do freshwater snails filter the water and are they considered beneficial in Koi ponds?

Freshwater snails are good for two things:

  1. Eating Algea
  2. Reproducing
and reproducing and reproducing and more reproducing. Usually adding snails to a pond is a bad idea, they can overtake a pond, clog mechanical filters, and be tough to get rid of. A good filter system is the most beneficial thing for a Koi pond.

Koi In A Livestock Tank

A friend of mine was telling me that I could put Koi in our livestock tank to help keep it clean. I don't think this is right? What do you think? -Melissa

A Koi will keep it clean, until their waste builds up. They will eat any grass and bugs that get into the tank, but they will pollute it with their waste. You are better off just getting a filter for the tank. If you have Koi, they will need a filter, food, care, ect. It is much simpler to just put a filter on for the tank.

A friend would like to breed Koi carp, could he do it? -Barbara

Anybody can breed Koi. Although, not many people know how to cull, combine breeding pairs, ect. If your friend is serious about breeding Koi, tell him to get in contact with a local domestic breeder. He might be able to volunteer his time and learn how to successfully breed Koi.

Friday, June 29, 2007

White Bump On Fin

I have a new koi and he has developed a white bump on his fin - I am wondering if this is a parasite. Also, he has a couple small blue fuzzy dots on his side which I suspect are fungus. How do I treat these two problems? -Betsy

That white bump is probably carp pox. Carp pox is a virus that makes solid waxy lumps appear on Koi. Carp pox usually appears in cold water and then goes away when the water temperature rises. Carp pox is not deadly to Koi, it is mainly a cosmetic issue.

The small blue fuzzy dots could just be color. If it is a fungus, treat it with a fish safe fungicide.

Koi in Dubai

I want to ask if koi fish can survive in middle east particularly in Dubai since the temperature here is rising and up to what degree of temperature does koi fish can tolerate? -Jasmin

Koi can live in water temperatures from 34 to 90 degrees Fahrenheit. If you have plenty of shade and good pond depth, I don't think that having Koi in Dubai would be out of the question. You may even want to look into installing a chiller to keep your water cool.

Breeding Koi



When the Japanese breeders spawn Koi, they usually put a couple males in a pond with one female. They will allow the Koi to spawn and then they will move the parents out of the pond so that they won't eat the eggs.

They should live in the well, make sure that you have good water quality. You might want to separate them if you want to breed, the other Koi will eat the eggs.

I wouldn't put any turtles in with they Koi, they might hurt the Koi and they might eat the eggs.

Can a high pH cause cloudy water? -Anthony

The most common cause of cloudy water in in Koi pond is poor filtration. If you don't have an adequate amount of filtration in your pond to remove organic and inorganic waste, they will build up and cause the "cloudy water". A little searching around the internet will reveal that high pH will cause cloudy water in swimming pools. A Koi pond is both very different and similar from a swimming pool. Both will have a filter system to remove debris. A pool needs chemicals to keep it clean and sterile. A Pond uses a biological or a chemical filter to keep it toxin free, but it is not sterile. If you have cloudy water, increase the amount of filtration on your pond.

Ogon Not Eating


Your Ogon that's shy is probably just got scared from the net that you've been using to try and capture the goldfish with. She also might feel sick from the small ulcer. When you feed your Koi, toss some food around the Ogon when it eventually goes to the surface. You can try to hand tame the Ogon again by putting your hand in the water with the food. Eventually it will get used to your presence and it will eat from your hand.

Tuesday, June 26, 2007


Koi and goldfish are both docile, so they get along good. A predator is probably getting in your pond and hurting your fish.

Sick Koi

I have this Koi fish in my pond at home. I think there's something wrong with him. He just sits there on the bottom and does nothing all day. Can you help? -Daniel

He is probably sick, with parasites or a bacterial infection. The best thing to do is get in contact with a local veterinarian that specializes in Koi health or a local Koi club. They will be able to tell you what is afflicting the Koi and how to fix it.

Scared Koi

I have this Koi in my pond and it seems like every time I walk past it, he is skittish and darts around in the pond like a madman. What in the world is going on?? -Anthony

Something probably scared your Koi in the past, and now it gets scared whenever someone goes by the pond. There's not much you can do other than trying to train it with food.

Do koi eat goldfish? -Daniel

Koi do not usually eat goldfish. The only time that could happen is if you have large Koi in a pond with tiny goldfish that could fit inside a Koi's mouth. Both Koi and goldfish are considered docile, so they get along great and won't fight.

How long does it take Koi to mate? -Anthony

Koi generally start to breed when they are at least two years old and are 12 or more inches long. Some Koi are reach sexual maturity sooner, some later. They generally spawn from spring to early summer. You'll know that your Koi have spawned when you start to see fry swimming in the algae at the sides of your pond.

Spring Fed Pond and Koi

I have a natural pond that is fed by a natural spring. The water runs into the pond at one end and exits at the other end. Do I need a filter? The pond is about 20 ft in diameter and about 2.5 ft. deep. I inherited this pond when I purchased the house. I need advise on how to maintain it and the Koi that are in the pond. The property sat empty for about a year and a half. - Masaie

Since the pond is spring fed, you probably don't need a filter system. The water is being constantly changed. This is also known as a flow-through system. For more information on Koi keeping, refer the the Koi keeping articles.

What gets ride of amonia and nirite? -Alan

There are a few things that you can do to get rid of Ammonia and Nitrite. They fit into two categories:

Short Term
  • Do big water changes
  • Add and Ammonia removing chemical to your water
Long Term
  • Add more filtration on your pond
The best solution is to increase the amount of filtration on your pond. Doing water changes every day can get old and adding chemicals to your pond can get expensive really fast.

Waterfall and Aereation

I now have 6 Koi in my pond. On hot days the water gets warm (80 degrees). I have a waterfall running. Will this be enough oxygen for the fish? -Anthony

The waterfall should provide enough aeration. Six Koi don't require massive amounts of aeration. It would be a different story if you said that you had 30 or 40 large Koi in your pond. If you are concerned about your Koi not getting enough oxygen, then go to a local Koi supply store or pet shop and get a good sized air pump with some good sized air stones. Hook everything up and put it in your pond.

How can I get my 4 Koi and 2 goldfish to eat from my hand? -Anthony

It takes time to train a Koi to hand feed. Start by putting your hand in the water with the Koi when you put food in it. At first they will be nervous and probably won't go anywhere near you. Eventually they will get used to the presence of your hand and will eat near it.

When they are used to your hand being in the water, cup your hand and put some food in it. Lower your hand in the water and hold it near the surface. They Koi will smell the food in your hand and will be curious. Eventually they will build up the nerve to eat from it. Training your Koi to eat from your hand is one of the funnest parts of this hobby.

Thursday, June 14, 2007

Koi and Other Fish

I have a large 1/2-acre pond in which I'd like raise Koi. What issues should I address prior to releasing the Koi in the pond? Specifically, will the Koi coexist with the existing species, e.g. perch, bass, and bream? -Chris

Koi are a carp. If those fish get along with carp, then they should get along with Koi. If you are really concerned about the fish getting along with each other, then get rid of the other fish and keep only Koi in the pond.

Raccons and Pond Depth

My pond is only 2 and a half feet at its deepest point. Will my Koi be safe from the raccoon? -Anthony

A great predator proof Koi pond will be four feet deep and will have sheer walls so that animals can't wade into it. Here's a video clip of a Raccoon getting into a pond.

Stressed Koi and Goldfish

I have 4 Koi and 2 Goldfish in my pond. Every time I walk by the pond they quickly dart down to the deepest part of our pond. Am I stressing them out? -Anthony

Something probably scared your fish in your pond. Walking by does stress them a little but don't worry about it. If you want to calm them down, add more fish to your pond.

How many gallons of water does each Koi need to have? -Nick

Each Koi needs about 150 gallons of water. This may seem silly when they are small, but when they get big, 150 gallons seems too little.

Mating Koi

Do male Koi mate multiple times with other female Koi or do they just mate once with one female Koi? -Bethann

Male Koi will mate multiple times with other female Koi. Monogamy is an abstract concept for fish.

Male or Female Koi

I have a bright yellow Koi in my pond (along with 3 other Koi). I suspect he is a male. How can I be sure? -Bethann

Here's an article about Sexing Koi.

I have Koi and they keep flicking. What do I do to treat this? -Alex

Your Koi probably have a parasite that's bugging them. Find a veterinarian or a local Koi club and they should be able to help you out.

Bubbles in Pond

There are bubbles on the top of my pond. They get in the way of seeing my fish. Can you help? -Dale

The bubbles at the top of your pond are caused by the dissolved organics in your water. The dissolved organics bind with oxygen, usually while the water is being agitated from an air stone or a waterfall. When the dissolved organics bind with oxygen, they float at the surface of the water as the "bubbles". Water changes will remove the dissolved organics from the water.

How Many Koi Can Be Put In A Pond

My pond is about 2500 gallons. How many Koi could I put in my pond? -Peter

The general rule of thumb is one Koi for every 150 gallons. Going by this calculation, you can put up to 16 Koi in your pond. Plan for the future and make sure that you will have adequate filtration for when your Koi get big.

Koi Flicking

I have a 10x10x5 pond, six weeks old, and my Koi keep flicking. Is there anything I can do? -Alan

Your Koi probably have some sort of parasitic infestation. Contact a local Koi club or veterinarian that specializes in Koi health so you can figure out what parasite is afflicting your Koi and what to treat it with.

Bubbles Near Waterfall

At the bottom of our waterfall is bubbles like someone put soap in the pond. The bubbles float all around the pond. How can I get rid of the bubbles? -Anthony

A quick short term solution is to take some pure alcohol and put it in a spray bottle. Spray a little on the bubbles and they disappear.

A long term solution is to do more water changes. The bubbles are probably dissolved organics in your pond. When they water thats full of dissolved organics runs over the waterfall, the agitation forces the dissolved organics to bind with the oxygen in the air. This causes the dissolved organics the float at the surface of the water and it looks like soap bubble. Water changes will lower the amount of dissolved organics in your pond, therefore lowering the amount of bubbles.

Do I have to put salt in my pond? -Anthony

There are both pros and cons with adding salt to a Koi pond. No, you do not have to put salt in your pond.

  • Salt makes Koi secrete a thicker slime coat
  • Salt kills parasites
  • Salt helps Koi with osmoregulation
  • Salt irritates Koi
  • Salt kills plants
  • Constant salt in ponds is creating salt-resistant parasites
  • Salt is only removed with water changes
Most people have salt in their ponds when they bring in a new Koi. This helps kill parasites and makes them have a thicker slime coat. After a while, they will lower the salt level to nothing with water changes.

Koi Health Problem

Koi not swimming much just huddled together at edges of pond near the top (not gasping for air).

Your Koi probably have a parasitic infection. Contact a local Koi club or veterinarian that specializes in Koi health to:
  • Find out what's afflicting your Koi
  • Plan a treatment to get rid of i


I recently asked about worming fish and I understand your answer about Flukes. My Koi swim in salted water, but following on about treatments for parasites, etc. Is there anything that we should be treating on an annual basis with medications as a precaution against the possible infestation of diseases? I now have a nice collection of fish and I want to make sure I am always doing the right thing by them to ensure their health and safety. Thanking You, William.

Koi health and disease is all about prevention, prevention, prevention. As the saying goes, an ounce of prevention equals a pound of cure. Adding salt to your water makes a Koi's slime coat thicker, which means that it has a better barrier against parasites and bacteria. There really isn't anything other than salt that you can use to treat on a annual basis to prevent a parasitic infestation or a bacterial infection. The best thing that you can do is make sure that you have spot on water quality and a low stress environment for your Koi. You see, parasites and bacteria are in the water at all times. The only time they really harm a Koi is when their immune system is down.

A Koi's immune system gets knocked down when:
  • There's poor water quality. (i.e. a buildup of Ammonia, Nitrite, or Nitrate)
  • They get stressed out often. (i.e. constantly being netted, animals going into pond, kids throwing rocks in pond, ect.)
If you prevent these things from happening, you should have great success with keeping Koi. If you are buying Koi, make sure you get them from a reputable place too. You don't want to buy a Koi thats loaded with parasites.

Is there such a thing as sunburn for Koi? -Patrick

If a Koi is kept for long periods of time in a indoor tank and then put in an outdoor pond, there is a chance that it could get sunburned. It is always a good idea to provide a place in the pond with shade so that your Koi have some place to go during the peak sunlight hours of the day.

Egg Bound Koi

I have a Koi which is about 10 years old. It has a dark swelling to its abdomen more noticeable to the right hand side of the fish. I've spoken to my local fish supplier who thinks that the fish could be egg bound. Could you suggest how the fish could be treated. Egg stripping was suggested? -Reg

Egg stripping is a preventative measure to keep a Koi from getting egg bound. When a female Koi grows eggs inside of her body, they either have to be expelled while mating or be re-absorbed. Sometimes the re-absorption of the eggs doesn't go so well and a female Koi will get "Egg Bound". Once a Koi gets egg bound, the only treatment is surgery to remove the tumor that grows from the impacted eggs. Contact a local veterinarian that specializes in Koi health and plan a course of action.

Blind Koi

I feel that my Koi is possibly blind. He just sits on the bottom of his tank and does nothing. He
used to be a very active fish trying to bite my fingers when I fed him but know he doesn't seem
to see me.

Can you please help me with any info or treatments
Thank you

It is a possibility that your Koi could be sick. When a Koi gets sick, they tend to isolate themselves. Contact a local Koi club or a veterinarian that specializes in Koi health and see if they will take a look at your Koi to get a better diagnosis.

Saturday, June 9, 2007

String Algae

Our pond is full of string algae, were are putting everything in. Can you help? -Daniel

You can try adding Bentonite to your pond. It forces the string algae to detach itself from the sides of your pond. You can also do large water changes, they will lower the amount of Nitrate in your pond (Nitrate is fertilizer for string algae). Maybe try cutting back a little on the Koi food a little.

If your pond was installed by a landscaper and it has rock on the bottom, remove the rock. Fish waste, uneaten food, ect. gets trapped in between the rock and becomes fertilizer for the string algae.

Algae problems

Our pond is all green. Algae keeps coming back. It's like we have to continue using the Algae substances day after day. How can I get rid of this algae for good? -Anthony

Algae is basically a weed. Most people don't want it in their pond and it can take over a pond if kept unkempt. Unfortunately, it is part of the Nitrogen Cycle. Your filter turns Ammonia into Nitrite and Nitrite into Nitrate. Nitrate is a fertilizer and algae is a plant, so if you have a bunch of Koi, they will produce a bunch of waste, which will then turn into a bunch of fertilizer.

Here are a couple of quick things that you can do to get rid of the algae:
  1. Run the water through massive amounts of vegetation (i.e. water lettuce, lilies, ect.)
  2. Do lots of water changes, (i.e. a 50% water change will remove 50% of the Nitrate in the water)
Two common types of algae found in Koi ponds are string algae and floating algae. String algae is the stuff that looks like huge tuffs of green hair. Floating, or suspended algae is the stuff that makes Koi ponds look like split-pea soup.

One of the simplest ways to get rid of string algae is to pull it out by hand. You can either grab it or use a toilet bowl scrubber to yank it off the sides of your pond.

A permanent way to get rid of the floating algae is to install a UV Light in your filter system. When the water is pumped through the unit, the UV light disrupts the DNA in the algae cells, effectively sterilizing them.

Wednesday, May 30, 2007

Should I have a constant concentration of salt in the pond? If so, what concentration? -Glenn

The only time salt is absolutely needed is when your Koi have a parasitic infestation. Salt hurts freshwater parasites because they are used to living in a saline-free environment. Salt irritates Koi, so it makes them produce a thicker slime coat. Some people keep a low level of salt in their ponds to help their Koi osmoregulate too.

From the Wikipedia article: Osmoregulation is the active regulation of the osmotic pressure of bodily fluids to maintain the homeostasis of the body's water content; that is it keeps the body's fluids from becoming too dilute or too concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution the more water wants to go into the solution. The pressure that must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water.

Animals in all environments (aquatic and terrestrial) must maintain the right concentration of solutes and amount of water in their body fluids; this involves excretion: getting rid of metabolic wastes and other substances such as hormones which would be toxic if allowed to accumulate in the blood via organs such as the skin and the kidneys; keeping the water and dissolved solutes in balance is referred to as osmoregulation.

If you want to keep a low level of salt, add one pound of rock salt per 100 gallons of water.

Koi in Aquarium

I would like to have Koi in an aquarium. I'm getting a 29 gallon tank and filter along with other stuff since I don't have a pond or have the money for it. Is there anything else I need to do to keep them healthy? Like vitamins? -Sydney

Just make sure that you have adequate filtration on your tank and you feed them a good Koi food. Maybe plan ahead and find someone that could take them if they outgrow your tank.

Worming Koi and Bottom Drains

Q1. I recently overheard a conversation about worming Koi fish at least once a year. I cannot find anything about this on the web, is this a normal practice and how or what do you use to do it.

Q2. I am shortly starting construction on a 6,000L pond, concrete floor and brick walls sealed with a pond sealer. My question, is it worthwhile putting in bottom drain in a pond of this size. Thank You. -William

I suppose that the people that were talking about worming Koi were talking about Flukes. Flukes are microscopic parasitic worms. Usually you can get rid of them with salt and Potassium Permanganate.

It is definitely worthwhile putting in a bottom drain. Anytime you have something that will automatically remove Koi waste and other debris from a pond, it is a good idea. There are even bottom drains that have built in aerators.

Small Pond, Large Koi?

I am only 20 years old and very new to the world of the Nishikigoi and becoming extremely interested in this hobby. I am worried about the size of my pond (only 90 gallons). How many Koi under 12" can this comfortably support??

and also...Could it support Koi larger than that until next year when
I have the money to work on a new pond? Any tips to help would be
much appreciated! Thanks! -Tweek

Your pond can probably support 4 to 5 small Koi, for a while. Eventually they will outgrow that size of a pond and will need a bigger area to live in. I would not get any Koi that are larger than six inches until you get a bigger pond. Larger Koi need more water volume, more aeration, more filtration, ect. You will run into problems with putting large Koi in a small pond.

I have lost two fish who seem to have dirt or old food coming out of thier gills? What caused this? -Dave

That dirt or old food is probably a fungus. A fungus is a secondary or tertiary infection. It basically means that something damaged your Koi and its immune system was weakened, so the fungus was allowed to take over. You need to find out what caused this and then take the appropriate action.

Friday, May 18, 2007

I have two Koi, the smaller slender one always swims under the larger rounder Koi. Why? -Phyllis

Koi aren't really anywhere near the top of the food chain, so they will do whatever it takes to not get eaten. Your smaller Koi probably feels safe while hiding under the big one. Maybe he will be more friendly if you put some more Koi into your pond.

How do you tell the sex of a Koi fish? -Angie

There's a great article about it here, Sexing Koi.

Do Koi fish die after giving birth like salmon? -Angie

Koi do not die after "giving birth". Koi don't actually give birth, they are egg layers. The females release their eggs and the males then fertilize them. When they reach sexual maturity, they are able to spawn every year for the rest of their lives. Most people find this out the hard way.

As in other animals such as a cat, if it is tri colored, is it a female only or can males be tri colored in Koi? - Rick

A Koi's colors do not determine its sex. Both male and female Koi can have the same colors.

Tuesday, May 8, 2007

What is a Sakura Ogon? -M Whitebrook

A Sakura Ogon, more commonly known as a Hariwake, is the metallic version of a Kohaku. If you are going to purchase a Hariwake, look for one with a nice Kohaku pattern and a nice metallic sheen.

Saturday, May 5, 2007

Do Koi Hide?

I recently purchased 3 koi and put them in my man made pond. I am unable to locate them. Do koi hide and stay out of sight? I do have a lot of rocks/barriers in the pond. -Mary

When Koi are introduced into a new environment, they are skittish and will hide for a while until they know that it is safe. They are probably hiding in your rocks, you'll be surprised to see how small of a space a Koi can fit into.

If you don't find your Koi for a long time, then something probably has happened to them, either getting sucked into a pump, a bad parasitic infestation, ulcers, or a predator.

Try putting some Koi food into your pond at dawn or dusk to see if they will come out to eat.

Sunday, April 29, 2007

Koi Attacked Update

The new Koi I wanted to introduce to the pond are 8-10 cms. When I put them in, the rest of the fish attacked them to the point of the new fish are having their fins and tails damaged. They were forced to the surface and were not allowed to submerge. -skinflint622

Sounds like your Koi in your pond were trying to breed with the new Koi that you introduced. There's nothing much you can do except putting the new Koi in a different pond or making a barricade in your existing pond to separate your new Koi from the existing ones.

Koi Damage

I have a beautiful Shusui, 3 years old, and about two weeks ago I noticed the markings just in front of the tail were missing leaving a patch about 1 cm square that is the underlying body color. I have inspected this closely and cannot see anything there that would have caused this, could it have damaged itself by flicking it's tail as they often do. Will the darker blue markings grow back and how long will that take, or will it stay as it is now. All the vital signs are good, ie, moving well, eating well, not showing any stress signs at all. All my other fish are really well and this has disappointed me because it was such a beautiful fish with perfect markings. Would appreciate your comments on the likely cause of this change in coloration. Thanking you, William.

Your Shusui lost the scales near its tail, probably by scraping against something. Koi scales take a while to grow back, about one year. Make sure that the area with the missing scales doesn't get infected.

Sunday, April 22, 2007

Koi Attacked

I have a pond with Koi at about 2 years old but when I put some new small Koi in the pond, the rest of the fish attacked them! Why? - skimflint622

Koi are classified as a "docile" fish, meaning under normal circumstances, they will not harm their own species and any other species of fish. You didn't elaborate much on the extent of the amount of damage that the new Koi received from your old Koi. My guess is that the old Koi were trying to spawn with your new Koi.

When Koi spawn, the males will chase the females around your pond and they will bump the females hard to try to make their eggs come out. If this is the case, then you might notice a lot of tin Koi swimming around in your pond soon.

Rainwater From The Roof

I would like to let the rain water fall from the roof in the pond, but I am wondering if it will be filtered quick enough in case of dust, especially at the end of a dry season (first rain)? - Benoit Raskin

I can think of one reason that putting rainwater that lands on your roof into your pond would be bad: if your roofing material leached something toxic into the rainwater. If it doesn't leach anything, go right ahead. Maybe let it rain a couple of times before you start putting the rainwater into your pond so that it can wash the dust off of your roof at the end of the dry season.

Monday, April 16, 2007

Is it okay to have underwater plants in a Koi aquarium? If so what kind would you recommend? Thank You -Lou

It's okay to put plants in an Aquarium with Koi. Although, the Koi might nibble on them. You can put whatever plant you want to with the Koi. You should also consider adding a CO2 injector and a special full spectrum plant grow light on the tank. The plants will definitely benefit from those.

Wednesday, April 11, 2007

Water Quality Problems

Hi, I have a problem with my water, the pH, Nitrate and Nitrite levels are all out. I am slowly losing my Koi due to this problem. I have done water changes and am still unable to bring the chemical levels back to normal. Advise Please. -Mohamed Iqbal

The worst of your named problems is the raised Nitrite level. Over time, this will hurt your Koi and it could cause a buildup of methemoglobin, otherwise known as "Brown Blood Disease." A buildup of methemoglobin will cause your Koi's blood to not be able to carry oxygen. A solution for a high Nitrite level is to increase your filtration on your pond. If you rely on biological filtration, you might have to wait a while for the Nitrobacter bacteria to grow in the filter and catch up with your fish load.

The second worst problem is your elevated Nitrate level. Although it is not toxic liek Ammonia or Nitrite, tests on reptiles and other animals have show that even a low concentration of Nitrate in their environment causes immune system and reproductive problems with long term exposure. A solution for high Nitrate level in your water it to do a big water change.

A high pH level won't harm your Koi, as long as it's stable. A fluctuating pH is what causes harm. I don't think that you have to do anything for the pH.

Some of my Koi are rubbing themselves against the bottom of pond,would pond salts help?

Salt is a treatment for the problem, but not a solution. Your Koi is probably rubbing against the bottom because of a parasitic infestation in your pond. You need to take a scraping with a microscope slide to find out what parasite is irritating your Koi. Then contact someone in your area, like a veterinarian, and plan for a course of action to get rid of the problem

Salt will make your Koi produce a thicker slime coat and at higher dosages, it will kill off certain parasites.

Breeding Butterfly Koi

I got a pair of butterfly Kois with metallic gray color but they are relatively young (about 4months old) and I wanted to breed these guys. When is the right age for Kois to breed? -Gio

Koi start breeding when they are at least 2 years old and when they are at least a foot long. I'd say that with two Koi, you have a 50/50 chance that both might be the same sex or that you have a male/female pair. If both of them are male or female, then you'll never be able to breed them.

Friday, April 6, 2007

Koi Dying For No Reason

Hi I was wondering if you could help me. I have a large Koi pond and since x mas, the majority of my fish have died. I have no idea whats wrong with them. At first they seem to bloat and then they float vertically, head up in the water, then they die. I have other fish, and they are unaffected. Have you got any idea what might be wrong or causing this? Any advice would be great.


It seems like your Koi have succumbed to an internal infection. That would explain why they would blow up, float funny and then expire. The other fish in your pond might have a better immune system or they might be unaffected by the thing that afflicted your Koi. The infection could have been caused by feeding when it's too cold, bad water quality, a suppressed immune system, ect.

Contact a local veterinarian that specializes in fish health & disease or a local Koi club. They will be able to provide you with more information. You need to find out exactly what caused the problem, a veterinarian or a club member will be able to visit your pond and will tell you how to fix it.

Thursday, April 5, 2007

Fin Damage

Hi! It's me again, my question this time is: Why do sometimes the smaller fish have a kind of bite on the tail, especially on the ventral fins? -Troppls

That piece missing out of the fins on the small fish is probably due to damage. There's a good chance that the fin might grow back as the Koi gets older.

Hi, I just want to know if Aeromonas is a contagious disease and if can affect the other fishes in the pond. -Eric

Aeromonas is not an infectious disease, it is a secondary infection. It appears after a Koi has had skin damage from: rough handling, brushing up against an abrasive surface (like a pointy rock), a parasitic infection, ect.

There are different strains of Aeromonas, some are worse than others. Aeromonas infections are treated with Tricide-Neo and/or antibiotic injections.

Here's part of an article from Wikipedia:

The Aeromonadales are an order of Proteobacteria, with six genera in two families.

Aeromonas is a gram-negative, facultative anaerobic rod that morphologically resembles members of the family Enterobacteriaceae. Fourteen species of Aeromonas have been described, most of which have been associated with human diseases. The most important pathoges are A. hydrophila, A. caviae, and A. veronii biovar sobria. The organisms are ubiquitous in fresh and brachish water.

Two major diseases associated with Aeromonas are gastroenteritis and wound infections,with or without bacteremia. Gastroentritis typically occurs after the ingestion of contaminated water or food, whereas wound infections result from exposure to contaminated water.

Although some potential virulence factors (e.g. endotoxins, hemolysins, enterotoxins, adherance factors) have been identified, their precise role is unknown. Aeromonas species cause: 1) opportunistic systemic disease in immunocompromised patients, 2) diarrheal disease in otherwise healthy individuals, and 3) wound infections.

Tuesday, April 3, 2007

Why do people keep Koi?

It's something that can't fully be explained, there are too many reasons. Here's one of them though:

Monday, April 2, 2007

Bio-Filter Cleaning Question

I have 5 small Koi fishes in an aquarium. How often must I clean the
aquarium? I do have a bio-filter, but the water is becoming a bit
murky. -Natasha

Your aquarium should be cleaned weekly to keep the water clean and clear. If a weekly cleaning gets to be too much, consider adding additional filtration to your aquarium or cutting down on feeding a little bit.

Robotic Koi

Nowadays, the Japanese aren't satisfied with just taking ordinary carp and breeding them to make beautiful colors come out. In the 21st century, they must use robots.

This is a video of another underwater robot, but you can see the Koi robot in the background.

Sunday, April 1, 2007

A couple of Koi questions...

A couple of items for your advice please.

Question 1-Feeding.

I give my Koi (16 of them) their main meal mid morning and I usually
soak the pellets for about half an hour before giving it to them. I do
this because they are so hard, they still float on the water even
after being soaked and I only give them sufficient that they can
consume in 5 minutes. Later in the day I usually give them a treat of
specialist food that they enjoy and over the summer they have grown
remarkably well. My question is: am I doing the wrong thing by
soaking their food first in a jug of pond water?

Question 2 - Salt in water.

At present I am adding salt at the rate of 50gms to 100Litres of
water. Is this sufficient?, and how do you test for salt content in
water? I have read many conflicting statements about the quantity of
salt that should be added so your comments would be appreciated. At
the moment I have some salt pool test strips and the reading on those
is 9.7 ppm/(mg/L). I assume you need to make an allowance occasionally
for evaporation because the water goes out of the pond but the salt
stays in, which in fact would increase the salt content by a small

Look forward to seeing your response.

Thank You,

Those are two good questions William. You don't need to soak your pellets in water before you feed your Koi, they have teeth that will crush anything that's hard. The Koi food manufacturer probably intended for the pellets to be put into the water when they're hard, by soaking them for half an hour, you may be breaking down the nutrients that are in the food.

Your salt level should be fine. Salt in the water actually irritates Koi, but in the process it gives them a thicker slime coat. Salt also helps with their osmoregulatory system. Instead of using pool test strips, you should try switching to a Koi pond salt test kit. The salt level in the water due to evaporation is usually neglagable, just don't let your pond evaporate halfway.

What temperature should the water be in a Koi aquarium? -Ashea

You should keep the water temperature at 70 to 75 degrees Fahrenheit in your Aquarium. This is the best temperature range for Koi, not too hot, not too cold.

Friday, March 30, 2007

I was wondering if Koi pond fish can go in an aquarium? -Lynn

A small Koi will fit in an aquarium, for a while. A small Koi can turn into a large Koi pretty fast, so if your going to find someplace for it to go. Here are some options:
  • You can buy a very large aquarium (i.e. 1500+ gallons)
  • You can build a pond in your backyard, if you don't have a backyard, go to the next option.
  • You can contact a local Koi or water gardening club, it'll probably have a member that would be willing to take your Koi and give it a new home.
  • You can give your Koi back to the pet store, they may even trade you for a new one.
Remember to have adequate filtration for the tank to make sure that your Koi has a clean environment.

Wednesday, March 28, 2007

Need help with my pond. I am in California, could you help with the maintenance? -Martha

Hi Martha,
I live about 1,500 miles away from California, so I can't help you with maintenance. Try contacting a local Koi club, you might be able to hire a member or someone at the club might be able to point you in the direction of a reputable company that can be of assistance. Maybe even contact Aquatic Coatings, the people there are really knowledgeable about Koi and filter systems.

Tuesday, March 27, 2007

How to treat Argulus

Argulus (fish louse) infestations in a pond are treated with Dimlin. When Dimlin is added to a pond, it prevents any adolescent Argulus from forming their exoskeleton, causing them to die off when they are adults. Consult Koi Health and Disease for more information and dosing rates for Dimlin.

Sunday, March 25, 2007

Koi and Aluminum

I am in the process of building a larger pond for my koi. Is it safe to incorporate a cast aluminum urn into the design? My plan is to pump water from the biological filter up through the bottom of the urn where it will then splash over the sides of the urn and back into the pond. -Eric

You should be fine with using an aluminum urn if you have pH neutral or alkaline water. If your water is acidic, the aluminum urn will harm your fish. When aluminum is in acidic water, it seems to cause respiratory problems for fish. Here's an article from PumMed on Aluminum Toxicity to fish:

Aluminium is acutely toxic to fish in acid waters. The gill is the principal target organ and death is due to a combination of ionoregulatory, osmoregulatory and respiratory dysfunction. The toxic mechanism has hitherto received little direct consideration and is unknown. In this paper the mechanism of acute aluminium toxicity is approached from a chemical perspective. Symptomatic evidence of toxicity is taken from the literature and combined with our own research to elucidate a biochemically sound model to describe a possible mechanism of acute aluminium toxicity in fish. The proposed model delineates the chemical conditions immediately adjacent to the gill surface and emphasizes their importance in aluminium's toxic mode of action. The mechanism is shown to be bipartite. Aluminium binding to functional groups both apically located at the gill surface and intracellularly located within lamellar epithelial cells disrupts the barrier properties of the gill epithelium. The concomitant iono- and osmoregulatory dysfunction results in accelerated cell necrosis, sloughing and death of the fish. The mechanism of epithelial cell death is proposed as a general mechanism of aluminium-induced accelerated cell death.

Koi Care in the Middle East

I live in Dubai, United Arab Emirates, I know nothing about Koi, I have
just purchased 5 small Koi (10 cm) they are in an outdoor pond thats
14 meters in diameter and 1/2 meter deep. I got some pond plant that they
hide in and eat. My questions are: 1. The winter here has mid 20 deg
c. day time and say 15 deg c. night time which I am sure is okay for
the fish, however, the summer can be extreme with high 40 deg c. Will I
have to put the fish indoors during the summer or if I buy large
lily pads do you think that the shade will be good enough? Secondly,
there is a decorative fountain in the pond that runs 24/7, will this
annoy the fish? I think its good for oxygenation as well as looking
nice. Thirdly, how much food should I give? Can one over feed?
whenever I put a teaspoon of food in they eat it in no time. I have
just read about fruit so I will try some of that. Finally, they seem
to be huddled together at the bottom of the pond allot, are they just
settling in? Are Koi normally shy?
Thanks Gary.

The winter in the United Arab Emirates seems to be pretty mild compared to the northern United States and Canada. Your Koi will do just fine in those temperatures. Your water should be warm enough to keep on feeding your Koi throughout the winter. The summer seems pretty hot. Make sure that you provide plenty of shade for your Koi and that the water temperature doesn't go over 33 degrees C. You can either bring you Koi indoors if the temperature gets too high or you can buy a chilling unit for your pond to keep the temperature down.

You are correct about the decorative fountain, it will aerate the water and it will not annoy the Koi. You can probably feed your Koi more food. Try giving them enough food to keep them eating for a couple minutes, a couple times a day.

When a Koi is introduced into a new environment, it will be nervous. Koi usually calm down within two weeks, eventually you may be able to train them to hand feed.

Tuesday, March 20, 2007

What is the right water temp for bio filter to start after winter season?

Your bio filter actually never shuts down, it just gets very efficient. This is due to the fact that cold water holds more oxygen, which is required to turn Ammonia into Nitrite and Nitrite into Nitrate.

There will be a significant less amount of Nitrifying bacteria in the filter itself, because Koi's metabolism slows down to a crawl in cold water. As the water in your pond gets warmer in the spring, the number Nitrifying bacteria that live in your filter will increase.

If you shut your filter system off in the fall, the bacteria would have all completely died off by now. It will take 4 - 6 weeks for Nitrosomonas and Nitrobacter to grow back.

Make sure to test your water frequently to check that your filter is working properly and there isn't an increase of Ammonia levels. Don't forget to do a large water change in the spring too. The oxidization of Ammonia and Nitrite by Nitrifying bacteria liberates Hydrogen Ions, which will lower you pH. Over time this will diminish the carbonates in the water, which could lead to a pH crash.

Monday, March 19, 2007

My pond froze over during the winter, are my Koi still alive under the ice? -Mark

There is a possibility that your Koi may still be alive. It depends of three variables:
  1. The size of your Koi in the pond.
  2. How many Koi you have in the pond.
  3. The size of the pond itself.
If you have only a few small Koi in a large pond that is several feet deep, then they should be fine. If you have a small pond with several large Koi, then the odds are against you and there's a good chance that they could have run out of oxygen.

The best thing to do right now is to get fresh oxygen in the water. To do this, pour hot water onto the ice so that it will melt a hole through it. Never chip at the ice, it's a great way to harm your Koi, their lateral line is used to sense vibrations. Then either put an air stone or a horse trough heater into the water to keep the ice open.

Saturday, March 10, 2007

What size tank should two Koi be in?? -Kayla

Two small Koi (4"-6") can easily live in a 55 gallon aquarium. Make sure that you have adequate filtration and aeration. Your Koi will eventually outgrow their tank. Then you will either have to get a bigger tank or donate your Koi to a local pet store, Koi club, or water gardening club, ect.

You can also build a pond for the Koi to live in during the summer and then use the tank to over-winter them.

Koi & Plecostomas

I have a 2 1/2 inch long Koi and a Plecostomus in a 10 gallon aquarium. Is there any issue with the algae wafers that I feed the Plecostomus and the Koi? What should I be feeding the Koi? He's eating gold fish flakes right now.

There should be no issue with the algae wafers that you are feeding your Plecostomus, they are not harmful to Koi. You should probably switch from goldfish flakes to a small pellet Koi Food. Goldfish food is meant for goldfish, so it may be missing some important nutrients that are good for Koi. Make sure that you do not overload your filter by feeding your fish too much.

Friday, March 9, 2007

Koi Ulcer

I have a 14 year old ghost carp with a swelling on his side near his rear fin also now his scales seem swollen and redness under the scales can anyone help me how to treat him???? -Liz

Your Koi probably has an ulcer. Ulcers are caused by the bacterias Aeromonas and Pseudomonas. There are two ways to treat an ulcer, injections with antibiotics or a Tricide-Neo dip if you don't like needles. Consult a local veterinarian that specializes in Koi health on the best course of action.

Just moved into a new home with Koi Carp pond with 22 fish, why would the water start to smell? -Tracey

That smell is probably ammonia buildup in your pond due to inadequate filtration.

A short term solution is to do a big water change and to cut down on feeding your Koi. Make sure to dechlorinate the new water before you add it to the pond.

You will need to get a good filter for your pond, long term exposure to low levels of ammonia in the water will poison your Koi. Here's an article with more on filtration.

Tuesday, February 27, 2007

My pump went out for a few hours, are my Koi OK? -Dave

Your Koi should be fine, unless you are very heavily stocked and its a hot day, then you should panic.

A couple of things happen when a pump stops pumping:
  1. The filter stops working and some ammonia will build up in the water. A few hours is not long enough for toxic levels of ammonia to build up. Your filter should remove any buildup shortly after you turn your pump back on.
  2. Another filter related thing, if your not pumping water and you rely on a biological filter to clean your water, your nitrifying bacteria that live in the filter are not getting any fresh food (i.e. ammonia, nitrite) or fresh oxygen. Don't worry, you won't lose any noticeable amount of bacteria in a few hours. The on;y reason you should be concerned over this is if your pump was off for half a week.
  3. The oxygen levels in your pond will drop, but only if you are relying on a waterfall to aerate your pond and you don't have an air pump/air stone to supplement it. During mild temperatures, a few hours won't hurt, but be cautious if its 90 degrees Fahrenheit during the day and your water temperature is 84 degrees Fahrenheit, you could run out of oxygen fast.

Sunday, February 25, 2007

What is the average life span of koi fish? -Leon

Most Koi live about 20-30 years. That is usually cut short due to an accident or a miss hap. There's a joke about how a Koi will live until the owner kills it. It is not uncommon to find a 30-60 year old Koi in some ponds around Asia.

The oldest Koi ever recorded was named Hanoko. Apparently, it lived to be about 226 years old and was kept in a natural pond in someones backyard in Japan. Hanoko was passed on down from generation to generation and even lived through many earthquakes. Hanoko was not a very pretty Koi, it was kept as a pet when the whole "selective breeding" thing just started, it was only a dull red color. Hanoko died back in the 1970's. The owners had the rings in its scales counted, like the tree rings in a tree trunk, to determine its age.

Are Koi fry usually born black and change colour wih age? -Eileen

All Koi start out as tiny dark fry after they emerge from their eggs. They soon start to develop their colors. Most will have a dull brown or just a single color, like orange. The reputable breeders cull out these and leave only the select few that have the potential to grow out into a beautiful fish.

Different varieties will turn different colors when they are small. Kohakus will turn an orange color with a pattern, Showas will remain black, metallic Koi will have a sheen, ect. As Koi grow older, their colors and patterns come out.

Thursday, February 22, 2007

Koi Keeping

Hi, this is just an observation that I have noticed since changing from Gold fish to Koi and that is that Koi are very intelligent creatures. Mine are waiting at the same spot each morning for their food as soon as they hear me coming and they each have their own personalities. I have one fish, a medium blue with green markings and dark blue spots down his spine (not sure of the type) and I call him "Bluey" and when I call his name he will leave the rest of the pack and come over to me so they do recognise their owners. Others will also come over and take food from my hand, some are more reserved and hang back until the food hits the water. It is also true about their hearing being very sharp because they hear me calling them and they come a-swimming straight over. Absolutely beautiful fish, wish I could keep more. Maybe a bigger pond? -William

I believe that Koi are one of the most tame fish that you can buy. They are easily trained to hand feed. I've seen some that sit at the surface of the water and wait for their owners to actually put food in their mouths. Koi keeping is a great hobby.

How many times do small Koi have to be fed in a day? -Butters

Small Koi, i.e. under six inches, should be fed about two or three times a day during the summer. Since they are small, they won't need very much food. In the spring and fall, when your pond water is cold, you should only feed them one or two times a day.

Monday, February 19, 2007

Is there a safe wood preserve that I can use on my pergola, over my koi pond? -Dawn

I would start by going to a local hardware store, like a Home Depot or a Menard's, and asking a sales person if they carry any non-toxic wood stain. Tell them that you have a pergola over a fish pond and that you want to make sure that the stain will not harm your fish. If you local hardware store doesn't have any non-toxic stain, then check with a local paint shop. If any of these places don't have what you are looking for, then they should be able to point you in the right direction.

Koi and Plants

My Koi fish are well fed but as soon as I try to introduce plants into the water they destroy them, is this normal? I have floating plants on the water which are OK until they hang down close to the water and then the Koi jump at them to pull them down. What can I do to get some greenery down into the water? -William

It is normal for Koi to tear apart your plants. Koi are omnivorous, so they'll eat just about anything that tastes good to them, which, unfortunately, includes your pond plants. Another problem that many people have is their Koi uprooting their plants from their pots because they love to muck around in the dirt to look for things to eat.

You can try to wall off a small section of your pond with boulders, so that you create an area where the Koi can not get to so your plants will be safe. You'll want to make sure that the water flow does not get restricted, otherwise you might run into problems with anaerobic bacteria and hydrogen sulphide.

You can also try building a floating cage for your plants. Although, it may not be very aesthetically pleasing. Black is a good color.

Many people actually have a separate pond built just for plants. That way they can enjoy both their Koi and their aquatic plants without having to worry about one tearing apart the other. If you separate plant pond, it's a good idea to put a couple small goldfish or Koi in it to take care of any mosquito larvae.

Can you use roof slates for water falls? Will they harm my Koi? -Rob

I assume that you are talking about actual slate, and nothing like fiberglass or asphalt shingles. Slate itself is harmless to Koi, so you should be fine with using them in a waterfall. Absolutely make sure that there are no anti-mold or any other chemical treatments that are applied on the shingles. The chemical treatments could poison your Koi. That is not really the desired effect of a new waterfall. Here's the blurb from Wikipedia on roofing slate:

Slate can be made into roofing slates, also called roofing shingles, because it has two lines of breakability: cleavage and grain. This makes it possible to split slate into thin sheets. Fine slate can also be used as a whetstone to hone knives. Because of its thermal stability and chemical inertness, slate has been used for laboratory bench tops and for billiard table tops. In 18th and 19th century schools, slate was extensively used for blackboards and individual writing slates for which slate pencils were used.

Slate tiles are often used for interior and exterior flooring or wall cladding. Tiles are installed and set on mortar and grouted along the edges. Chemical sealants are often used on tiles to improve durability and appearance, increase stain resistance, reduce efflorence, and increase or reduce surface smoothness. Tiles are often sold gauged, meaning that the back surface is ground for ease of installation.

Slate is often used as a decor in freshwater aquariums. Slate will not alter the chemistry of water {except in the slate containing feldspar which may leech silicates into the water resulting in excess diatom growth in marine aquaria). When broken, slate produces a natural appearance while remaining relatively flat and can be easily stacked. Silicon glue adheres to slate, creating a non-toxic bond to secure it. It is also used in stairs and pathways for the same reasons.

Slate. (2007, February 18). In Wikipedia, The Free Encyclopedia. Retrieved 20:26, February 19, 2007, from

What's the meaning of the colors that Koi have?

Here's a bunch of translations of the color names:
  • Ai - red
  • Aka - red
  • Beni - red
  • Budo - purple
  • Cha - tea or brown colored
  • Gin - (pron. geen) silver
  • Hi - (pron. hee) red
  • Ki - (pron. kee) yellow
  • Kin - (pron. keen) gold
  • Midori - (pron. meedoree) green
  • Orenji - (pron. orenjee) orange
  • Purachina - (pron. pooracheenah) platinum or metallic white
  • Shiro - (pron. sheeroh) white
  • Sumi - (pron. suemee) black
  • Yamabuki - (pron. yahmahbookee) metallic yellow

How do you tell a male from a female koi? -Dave

There are a bunch of subtle differences that male and female Koi have. They have different shaped fins and a different body conformation. Here's an in depth article on the subject:

Saturday, February 17, 2007

Goldfish & Koi

Is it possible that a 2 years old carassius (A goldfish) could kill a new 4 month old koi? They lived together in a 1000 gallon open outdoor pond. -Troppls

Both goldfish and Koi are docile, they will not eat or damage each other in anyway. There are a few things that may have happened to your Koi:
  1. It may have been eaten by a predator.
  2. It may have gotten sick and died.
  3. It could have had an internal defect and died from it.
  4. It could have jumped out of your pond and then flopped itself under something, hidden from view.
It's usually a good idea to cover your pond when you introduce a new Koi into it. They tend to be skitterish when they get new surroundings.

Thursday, February 15, 2007

A Black Spot

I have two Koi and two goldfish in a 600 gallons pond with a 1200 pump mag-Drive and a Jebao PF-3 Bio Filter with 11 Watts UV. This morning one of my goldfish had a small black spot on the side of the belly. I have been doing water tests weekly and I don’t see anything wrong with the water. I don’t know what could be wrong. Any Ideas? -Patrick

The black spot on your goldfish is probably a small cosmetic flaw, caused by a bad gene. Koi people usually call it Shimi. It has nothing to do with water quality and it does not affect their health.

There is a small possibility that it could be a parasite, like a fish louse or an anchor worm. But it's unlikely and you'd notice that your goldfish would probably be acting funny.

How many Koi can one can safely keep? -William

The standard that most people go by is this:
One Koi for every 150 gallons of water in a pond, or 1:150.

150 gallons of water per Koi will give them plenty of room to swim around and plenty of space to grow out.

Some people go much higher than 150 gallons per Koi, some go up to 1,000, 1,500 or 5,000!

Many hobbiests do get concered if they have 22 or 23 Koi in a 3,000 gallon pond. They don't need to worry, it only lowers the ratio by a few gallons.

The amount of filtration that you have for your pond is far more important than a gallon ratio. Being underfiltered is far worse than being overstocked.

Bakki Showers. What do you know and are they a good way to filter the water? -Cam

Nitrifying bacteria in ponds need three things to thrive:
  1. Water
  2. Food (Fish Waste - supplied by your Koi)
  3. Oxygen
A Bakki Shower is a wet/dry filter.

A Bakki Shower is basically a bunch of boxes (chambers) with perforated bottoms that are stacked ontop of eachother and then filled with filter media. Water that is taken from the pond is pumped up into the top chamber, where it then proceeds to fall down through the rest of the chambers and then back into the pond. When the water falls and hits the filter media, the nitrifying bacteria that live on it do their thing by converting the toxins that Koi produce into Nitrate. Also, the water hitting the filter material creates a large amount of agitation, making it absorbs a lot of oxygen, which both Koi and Nitrifying bacteria need.

The Bakki Shower will filter your water and aerate your pond at the same time.

There are a few of downfalls for this type of filter:
  • A Bakki Shower provides no mechanical filtration.
  • A single Bakki Shower is only good for a small to medium sized pond. A large pond will require several Bakki Showers, which will increase the overall price of a pond and the overall noise level.
  • A Bakki Shower will create some noise. If you prefer you water feature to be peaceful and quiet, this may not be a good choice for you.
Bakki Showers are good for filtering a pond. They are relatively easy to install and easy to maintain.

Is There A Way To Enhance The Fishes' Colors, ie Food ect. But In A Cheap Way? -Kevin

The easiest way to enhance a Koi's color is by letting it get plenty of sunshine. Good old vitamin D will really bring out the color in your Koi.

You can also give your Koi food with carotenoids in it. Carotenoids are what give Flamingos their nice pink color. When a Koi, like a Kohaku, eats food with carotenoids, it enhances their red color. Although, you also don't want feed it too much to them, because their white color will start to turn pink.

Wednesday, February 14, 2007

Koi Q & A

Koi Questions and Answers was launched today. We're looking forward to everybody's questions. If you look to the right, there is a message box to type your questions in.