Monday, August 31, 2009

Feeding Time

This large Showa is hungry. Watch him gobble up a bunch of Koi food in this video.

Average Koi Pond Cost

My family wants to get a koi pond. One of our friends also has one, so he can help. The only problem is the money. How much does the average koi pond cost? - Jake

I assume you are building it yourselves, to save on labor costs.

It depends on the size and amount of filtration the pond will have. A small pond with high end filtration equipment will probably cost the same as a medium or large pond that is either poorly filtered or has DIY (Do It Yourself) filtration.

DIY filtration usually involves a large container, like a barrel, that is filled with bioballs. A high end filter system usually involves a pressurized bead filter, UV sterilizer and a protein skimmer.

DIY filtration costs less but involves much, much more maintenance than equipment that you can buy from a dealer. How much more maintenance? Up to about 10 times more. Don't think that's true? Cleaning a pressurized bead filter takes about 15 minutes a week. Pressurized bead filters backwash just like a pool filter, you only need to turn a valve to clean them. Cleaning a barrel full of bioballs takes about an hour (You will get covered in smelly pond scum and fish waste).

Here, it's broken down for you:

DIY Filtration
More time consuming - less money

Pressurized Bead Filter
More money - less time consuming

You will get tired of getting covered in goo every few days eventually.

Green Water
There really isn't a safe way to add a DIY UV light to your pond. You need a purchase a manufactured unit from a dealer. UV lights prevent algae from growing by sterilizing them, so the water in your pond stays clear.

Some people add large amounts of barley to their pond as a cheap alternative. A bacteria that grows in the bales kills algea. Who wants to have a bunch of bales of barley in your pond? No one. The bacteria that kills the algae takes two months to grow, so if you live in a cooler climate you better start the pond up early!

Dissolved Organic Compounds

Their is only one decent protein skimmer for a Koi pond, it's called a Clarity Protein Skimmer. They will get very small particles of waste that are dissolved in the pond water. It's almost impossible to do a DIY version of one of these, your better off buying one.

DIY filtration won't have a warranty or a guarantee that it will be adequate for your pond. When you purchase a filter from a dealer, they will help you size the equipment for your pond. Manufactured equipment can have warranties up to 4 years or more!

Here's the pricing, for a small (1,200 gallon), medium (3,000 gallon) or large (5,000 gallon) pond, with high end filtration and DIY filtration:

DIY Filtration:
Small: $1,500.00
Medium: $3,000.00
Large: $5,000.00

High End Filtration:
Small: $2,500.00
Medium: $4,000.00
Large: $7,500.00

Why are the Fry Ugly

I have both koi and goldfish in a 2,500 gal. pond. They were very active during breeding season. The babies are about 8 weeks old now, but 75 of them look just like minnows. Dark gray/brown on top with a dark stripe down the middle and a white belly (just like a minnow). The other 50 babies are pale orange. Why do they look just like minnows? - Gingrich

The majority of fry revert back to the natural color of their ancestors, which is why the Japanese breeders cull the majority of their fish. The carp that Koi came from are a dark black color.


How do I train my koi to not run and hide every time I come around. I tried to not feed them for 3 days but they still hide till I leave. - Steve

Are you moving around a lot when your by them? Try remaining still and giving them some food. Keep at it and then start moving around a little when you are feeding them. Soon enough they will associate your presence with getting fed, so they shouldn't be shy.

Fall Good Time To Buy Koi?

Dear Sir,

I have just completed my backyard pond. Its end of August now in Boston and Fall is marching on. I have scoped some sites selling 5-8 inch koi and I am wondering if I should go ahead and populate my pond with the small koi now or is it the wrong time of the year and wait for spring? I have an aireator, flowing water, filter installed for water hygiene.

Thank you


You can certainly find some great pricing on Koi at this time of the year. Although most dealers stock will have been picked through very thoroughly.

Keep in mind though, you will only be able to appreciate your Koi for only a couple months before you'll have to winterize your pond. Make sure you know how to keep Koi outdoors during the wintertime too (unless you plan on keeping them in a tank indoors). Winter and spring are very hard on Koi.

Make sure whoever you buy your Koi from quarantines them when they first arrive and tests for the KHV virus.

Side fins closed not protruding - Derek

Sounds like your fish is sick with an infection. Have a vet take a scape with a microscope slide and a tissue swab for a bacteria susceptibility test, so you know what antibiotic to treat with.

True Colors

How old do Koi need to be before having their true colors? - Tony

It depends on what type you are talking about. Some Koi, like a Yamabuki Ogon, have their color as soon as they are born. Other Koi, like the Showa, take years for their color to develop.

Blacky Baby Fry

Hello, can you help me? My Koi carp mated 3 mouths ago and I have loads of fry. They are about one inch long now, but they are still all blacky gray color. When do they get their colors? The koi carp that bred were all different colors. I have no black Koi in my pond. Will they change? - Darby

Ninety five percent of fry that Koi produce have little or no color. Unfortunately, he fry in your pond probably fall into that percentage. Koi have their colors as soon as they emerge from their eggs. Some change, but since yours were from a random spawning, they will probably stay black.

Can too much clay do any harm to koi?

Yes, adding too much bentonite (Koi clay) to the pond can clog the filter system, so your water quality will go down.

Tuesday, August 25, 2009

How to Breed Koi

It is a very laborious process.

You need good brood stock, which will cost you several hundred thousand dollars or decades of careful breeding. You will also need equipment, facilities and a great staff. You also need a lot of time.

The oyagoi (parents) are placed in ponds that are full of spawning matting. For a few hours, the female will ready itself to release the eggs onto the spawning matting. When she ready to expel the eggs, you'll need to coax them out of her into a bowl. The male is then taken out of the pond, anesthetized, and then has his sperm is extracted. When the sperm and eggs are gathered, they are mixed together to achieve fertilization.

The eggs are then put on the spawning matting that is in the ponds. This must be done carefully, so they get attached to the matting correctly.

Within a few days, your Koi will hatch and you will see the fry swimming around in the pond.

Now you'll need to move them into a large pond and feed them a decent food that is full of packed with nutrients.

When they grow large enough, you'll need to cull them. This involves sitting for days on end while you sort through tens of thousands of baby Koi. You'll whittle them down until you are left with a few thousand of your best fry.

After the culling, the fry will go into a mud pond to grow until they are large enough to sell.

You'll repeat this process over the years as your Koi grow. You'll remove the ones who lose their color or have deformities. You'll also separate out some Tategoi, Koi which have future potential but don't look the greatest right now.

The process can get very complicated, here's what you have to be knowledgeable in:
  • Fish Husbandry - You'll need to know how to take care of thousands of fish and keep them healthy. One bad disease outbreak and years of work will vanish (not literally). You'll also need to know how to filter your display ponds.
  • Management - You'll need to know how to keep your employees in line.
  • Selling - It doesn't matter what quality of Koi you produce if you can't sell them.
  • Importing/Exporting - Why limit yourself, but you do need to keep up on all that paperwork.
  • Funding - It can take up to a few years to produce a single quality Koi, what will you do for cash flow in the meantime?
  • Construction - Those mud ponds aren't going to build and maintain themselves.

Tons of Eggs

My Koi just let out massive amounts of eggs in a 150 gallon pond. What can I do with them? - Leroy

You can either raise the fry or you can try removing the eggs from your pond. You can also let your Koi eat them, which they tend do do anyways.

If you let the fry grow, your going to need a place for them to live eventually. Hundreds of Koi can't live in a 150 gallon pond.

Pictures 8-25-09

Butterfly Listing

I have a 4 inch butterfly Koi that is listing to it's left side. It swims around fine, but i am concerned because this has only been noticed in the last week. what can I do to help restore this fish to full health? I have given all the fish (about 15 total) the first treatment of potassium permanganate with no visible distress noted and plan to give two more treatments. - Harry

Sounds like your Koi has an internal problem that keeps it from swimming normally. You can check to see if it has an ulcer or parasites that are bothering it. These may be what is causing it to list. If it isn't a parasite or an ulcer, the only thing you can do is wait for it to correct itself.

Three Koi Sick

Three Japanese Koi keep laying on there side as if there dead. All other fish common carp and Koi all ok. Japanese koi losing the bright color but are still feeding ok. - Martin

Sounds like your new Koi are sick. Koi loose their color when they get an infection. You need to get in touch with a veterinarian that specializes in Koi health. They will be able to diagnose what is wrong with your Koi.

Dropsy or Eggs?

I have a Koi that appeared to have dropsy. We treated the pond and it didn't seem to work. All of the sudden the fish is back to normal size so I assume this was eggs but the fish was like this all summer. It also has a half dollar size wound that came up on its side after whatever was there was released. Do you have any ideas on what could be going on? I have salted the pond and I am using Melafix and Pimafix. I am very much an amateur at this so any professional advice you could give would be appreciated. - Claudia

It could have been eggs that caused your Koi to swell up. Usually dropsy is a sign of organ failure, Koi with dropsy rarely live past a few days. It is even rarer if a Koi comes out of dropy.

It's good that you salted the pond, this will make your Koi's slime coat thicker. If that wound doesn't heal up, try some Tricide-Neo. It is a potentiated antibiotic, so it is effective with resistant bacteria.

5000 Gallon Pond

It looks like there are about 20 medium sized Koi in this pond. It has a nice small waterfall falling near the middle of it.

Treating An Ulcer

They take the fish out of the pond and treat it with some sort of medicine that's in a pressurized can. I guess that's how they do it in Holland. Interesting way of applying medicine anyways.

Holland Koi Show 2009

Here is the video from Holland's 2009 Koi Show. There are tons of beautiful Koi in all of the tubs.

Feed Baby Koi

Baby Koi need to eat just like their larger counterparts. They feed on decapsulated brine shrimp, infusoria, or crushed Koi food (it will be powder). You'll need to feed them several times a day. Make sure you have pristine water quality too, the fry are sensitive to water chemistry.

Monday, August 24, 2009

Pictures 8-24-09

Koi whirlwind feeding frenzy!! Second batch 8-21-2009

From AiNishikigoi on youtube:
This here is the product of several pairs of Japanese Koi bred in separate holding tanks. The frys were then raised for several weeks in their respective tanks before I combined them all together for ease of transportation and maintenance. They are at about 1.5-2.5'' in length as of 8-21-2009. This batch is the second of the year, the first one was produced in early May and was the product of a Sakai male x Hoshikin Kohaku female (video will be uploaded after the last cull).

Within the mix will be a varied amount of Gosanke, Utsurimono, Bekko, Asagi, Goromo, Ogon, and a few other variations. There is also a diverse representation of doitsu as well (Shusui). The quality of the genes should all be there as a few of the parents were from Momotaro, Shinoda, Marudo, Yamamatsu-Matsunosuke, Ofuchi, and other high quality breeders and farms. Hopefully all this hard work would yield a few show-worthy koi. But at the least, they are very adorable!! I must admit though, they do grow fast :-(

I was compelled to record this as they gathered in 'whirlwind' formation during feeding time. I thought it was pretty cool and wanted to share with everyone. I am located in Sacramento and San Francisco. If any one is interested in the koi or need general information regarding pond care, let me know! I'm always available to help. Thanks!

Very truly yours,


Japanese Pond

An award winning Koi from Miya Jima, Japan.

Building Pond

A slideshow of a pond being constructed in Germany?

Koi Fish Playing at Night

Pond lighting is a great feature to have in your pond. It almost seems in this video the Koi love to play around with the lighting. Enjoy!

Attilatomi's Pond

Here is a video clip of a nice Koi pond.

Green Water

Green water is caused by algae. Algae feed off of the waste that the filter converts into Nitrate. If you have a ton of fish in your pond, you'll have a ton of Nitrate and that will fuel an algae bloom. The best way to get rid of algae is to use a correctly sized UV light. A UV will sterilize the algae, so it can't take over your pond. Your pond will clear up within a week of adding a UV light.

How to rid your pond of argulus?

Argulus, or fish louse is a parasite with an oval body and a proboscis mouth that it uses to feed off you Koi. You can pick them off your Koi with a tweezers. To eradicate them from your pond, check out the entry in the book Koi Health and Disease by Dr. Erik Johnson.

Sunday, August 23, 2009

Pictures 8-23-09

Keep Koi Indoors?

Could I keep a Koi indoors? Do Koi do okay by themselves, or do they need to be in a group? How big of a tank would it need? - Nicole

Yes, you can keep Koi indoors. Make sure they have all the basics: filtration, aeration, sunlight, etc. The tank will need to be fairly sizable, since Koi can grow up to three feet in length. A solarium is the best place for an indoor Koi pond/tank. 1,500 gallons would probably be the minimum size of a tank that would permanently house Koi.

It doesn't have to be an aquarium, I've seen a lot of cool tanks made out of concrete or wood. The best ones have a Polyurea liner.

They do need to be in a group. If you have only one Koi, it will be very skittish and afraid.

Just look at this poor fish, he is all alone and his tank is way, way to small. Please don't ever do this, it's cruel:

Jumbo Koi Swimming Video

Jumbo Koi fish are swimming around in a pond in this video.

Jumping Behavior

Do big pond Koi often jump out of water for bugs , etc? - Kathy

Yes they do! Koi jump if they see a bug on the surface and they swim at it very fast. They will also jump if they are startled.

Gold Color

I have a black and white Koi that is changing to gold. The koi is about 8 years old. Is this natural or is this a disease?

It is probably natural. The gold color is coming out with age, unless your fish starts acting funny, there's no need to worry.

Parrot Fish

I just got a Koi fish in my tank with one 12 inch parrot fish and it won't stop biting the Koi's tail what can I do about this? - Jason

You put a docile fish in a tank with an aggressive one. The only solution is to separate the fish.

Friday, August 21, 2009

Pictures 8-21-09

Ojiya Manhole Cover
Eating Underwater
Pond with Blue Frog
Sitting by Pond
Ink Drawing

Salt Water

Can Koi fish live in a salty water? - Loi

They can live in water with a small salt concentration, about 1 pound per 100 gallons. People typically use 3 to 5 pounds per gallon when treating parasites. You have to be careful and test your salt levels frequently. Water evaporates and salt doesn't, so its concentration will increase. If you add salt, make sure it is pure and doesn't have any additives like Iodine.

You can remove salt by doing water changes.

Pond Pump Went Out

My pump went out during the night, how long will my koi live without a pump? - Angela

You Koi will live as long as these things don't happen:
  • They run out of oxygen
  • Ammonia levels get toxic enough to poison your fish
A lot of people rely on a waterfall to aerate the water. So if your pumps stops working, your Koi lose their source of oxygen.

The pump runs the filter, which relies on bacteria to filter the water. The bacteria need food (Ammonia) to survive, and without the pump running, they lose their source of food. After about 12 hours, the Nitrifying bacteria will start to die off. If you lose the colony on your filter, it will take a while for it to come back.

The longest a pond system should be shut off should be no more than 10 hours in an emergency.


One of the Koi fish in my pond jumped out of the water like a dolphin. He jumped twice. Can you tell me why he did it? - John

There are a couple reasons why your Koi was jumping:
  • It could have been going after a bug.
  • It could have had an itch, they don't have arms to scratch with, so any external force will do the job.

Breeding Age

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 usually have to be at least 2 years old to spawn. Usually they are a little larger than yours, but you probably have small ones...

Sanke Broken Tail

I have a Female Sanke Koi. Her tail appears bent in one area as if it were broken and her bottom rear fin had a a blood clot in it. The tail is healing and growing back but the bend appears permanent. I could not find the answer anywhere on this. Would appreciate any response. Anthony CA

Spawning Signs

How will I know if my fish are spawning and where would they spawn? My Koi carp seem to be bullying another fish... - Angie

Your fish will be bumping into eachother, a lot. You will notice behavior for several hours. They will spawn in plant material, their eggs need something to attach to.

Thursday, August 20, 2009

Cool Picture

Koi Swimming
This photo of a bunch of Koi swimming around is awesome!

Choosing Koi Video

Here is a video clip on choosing Koi fish. There are some standards to follow if you are planning to show the fish, but if its for your pond, choose a fish that you like.

Pictures 8-20-09

Pond Laser
Koi Swarm
Koi Sunglasses

Two Fins

I have a koi fry that has 2 tail fins, one vertical and one horizontal, looking like a star. What would cause such a thing and should I be concerned? - Pam

That's not a Koi, that's a fancy goldfish. Koi only have one tail and it is vertical.

Selecting Tosai

TateGoi Koi Masterclass Video 1: Selecting Tosai. With Denis Wordsworth and David Lawton. Produced by Nathan Rae Productions.

Fountain Filtration

I have a waterfall type fountain and have put two Koi in it. How do I go about putting a filtration type system in it to ensure that they stay healthy? Recommendations? -Shane

Koi produce two types of waste:
  • Feces
  • Ammonia excreted by the gills
You will need two types of filtration to combat this:
  • Mechanical Filtration
  • Biological Filtration
Mechanical filtration will catch the solid waste so you can dispose of it quickly and efficiently.

We rely on bacteria to convert the Ammonia into less harmful chemicals, hence the term, biologica filtration. The bacteria need a place to grow, so a biological filter will have a lot of filter media for it to colonize on.

There are filters that do both biological and mechanical filtration. These are known as pressurized bead filters. You can find out more information on them here.

You may also want to get a UV light. It will keep the water in your fountain from turning green. More on those here.

You can pipe the equipment inline with your fountain, so the water gets filtered before it goes through.

My Koi with orange color are fading to white? - Nadine

Bad genetics.

Your fishes parent's color probably did the same thing. That why most people buy Japanese Koi, that are imported. Japanese Koi will keep their color 20+ years. Most states usually have at least one dealer.

New to Koi

So i just won some baby koi under 2" long, i have them in a plastic tube in partial shade,(temporary) indoors,and it is about 2' long,and about 1'wide,and about 5-6" deep, i have 2 koi and one goldfish,(all uner 1-2")i feed them goldfish flakes(they eat them all) twice a day in a food bowl lowered into the water,leave for about 5mins,come back and its gone,there is a thin layer of pebbles(covers complete ground minus 1 corner were i feed them)and some shells,and a bubble tube under one so they come up through it, anything i am doing wrong? i also plan on getting a filter, what kind should i get? do i relay need to "cycle" the water? and how? and what is cycling g? I have been researching for hours ,but i always pull up outdoor ponds, not indoor ponds. - Anna

Those poor fish, you should have them in a tank ASAP. An aquarium filter rated for the tank that you put them in should work. That's the nitrogen cycle your reading about. By cycling, you make sure you have enough bacteria in the filter to keep up with the waste your fish produce. It takes about a month and a half to completely cycle a filter. Indoor ponds are rarer, do to their expense. Aquarium are what most people have.

Introducing Fry Into Pond

I introduced three of my koi fry back into the main pond after they had reached two inches long with disastrous results. One was eaten and then spit out. He is now missing most of his tail. Will it grow back? (they are all back in the smaller pond now) At what size should I reintroduce them to the main pond? - James

I'd wait until they were at least 4 inches long, they'll swim a lot faster. Predators will have a harder time catching them.

Farm Tour

A video tour of a Koi farm.

Aquarium in HD

A couple of Sankes swim around in a fish tank. Filmed in High Definition.

Japanese Carp Fish Pond

THE word "koi" comes from the Japanese, simply meaning "carp." It includes both the dull grey fish and the brightly colored varieties. A homophone of koi means "love, affection" and koi are therefore symbols of love and friendship in Japan...

Baby Color

My baby Koi seems to be all black, would they change color? If so when do they change?

Japanese breeders cull up to 95% of the fry that Koi produce. The reason, 95% of Koi have little or no color that's worth anything. Your babies will probably stay the same color. They are special though, if you hadn't decided to build a pond, they would never have existed!

Tuesday, August 18, 2009

4 Step Kohaku

Here is a 4 step Kohaku. It is 3 years old and 17 inches long. It looks like it has some stray Hi (red) spots. A good pond fish though.

Koi Pond 2.0 Demo

Bill Trost, designer of Koi Pond for the iPhone and iPod Touch, demonstrates the new features in the free 2.0 update to the popular application. There seem to be a lot of new aesthetic features. You can also control how many Koi are in the pond.

Pictures 8-18-09

Koi Earrings
Nishikigoi Water Color
Koi Photo
Koi Tattoo

Touching Up

If you have steady hands, you can touch up a Koi. Note: this is not an instructional video, Koi Blog is not liable for anything.

Pump Too Large

Can I use a large pool pump that would be used with a home made filtration system using drums with different media for a koi pond. I also have a 3/4 hp pump and my neighbor is saying it is too powerful to use on a koi pond. Is this true? - Florence

You only want to circulate the water in your pond through the filter system about once ever hour or two. If you do it more than that, it creates too much current of the fish and the water will flow over your media too fast for the bacteria to filter it. Check out the pumps flow rate to see how much water it circulates an hour.


A 2,000 gallon pond can handle any pump that puts out 1,000 to 2,000 gallons per hour. Remember, the filtration and waterfalls will slow down the flow rate due to head pressure, so a larger pump may work. Consult the pump manufacturer for a definite answer.

Koi Live Outside Water

Can Koi go out of water? - Emma

They are fish so the answer is no. They can go out for very short periods of time, like when you take them out of the bag after you bring them home.

17" Showa

This beautiful Showa is swimming around in a tank.

15" Average Weight

What is the average weight of a 18" koi? - George

I think its around 12 to 15 pounds. An easy way to tell is to fill a Koi tub with some water, weigh it. Then put the fish in the tub and weigh it again. Subtract the difference and you have your Koi's weight.

Round Belly

One of my Koi is getting very, very round in her belly. I think she is unable to pass her eggs. She is isolating herself from the rest of the group and appears to be having trouble swimming as she is so large. She is eating normally - is there something I can do? Many thanks, Michel

Your Koi might be egg-impacted. Normally, if Koi if Koi don't expel their eggs, they re-absorb them. If something goes wrong and they don't, the eggs will then turn into a tumor. The only way to remove the tumor is to have a veterinarian perform surgery.

Tank Plants

(still got the same tank) what plants(if any) should i put in with my koi/goldfish?it is about 4-6" deep, and what shouldn't I put in? also, whats the best(preferable rather cheap, im on a budget,and lasts a long time)to give them? and is it normal for them to just kinda sit there on the bottom and swim occasionally(they look healthy)i also just put them in 1 day ago,or should they be on the surface? - Anna

Any aquatic plants that don't have any spikes or leech anything into the water will be fine for your Koi. If they are swimming around, they are healthy.


Ok, I still have the same tank (a breeders tank, someone called it) but I am planing on buying (just till they outgrow it) a small kiddy pool, one you see toddlers(humans) playing in, is the plastic ok for them as long as i doesn't get too hot? -Anna

You are correct, just as long as it doesn't get too hot and the plastic doesn't leech any harmful chemicals into the water. Make sure you give them plenty of filtration and fresh water.

Tancho Showa

A Tancho Showa will have all the red (Hi) color in a circle above the head. It has a black base with white bands of color.

Shiro Utsuri

A Shiro Utsuri is a black Koi with bands of white color on it.


A Bekko is a white Koi with black spots.

Monday, August 17, 2009

Pictures 8 17 09

Aka Matsuba
Feeding Frenzy
Aka Matsuba and Shiro Utsuri

When do Koi first breed? - Tdinnie

Koi reach sexual maturity when they are at least 2 years old and about a foot long.

A homemade Koi Pond

Christopher Heede of Arizona shows the house he built, along with his front yard Koi pond (Christoph Ceramics). Check out the Koi muching on watermelon at the end!

Above Ground Koi Pond

This video has a beautiful example of an above ground Koi pond. When you have an above ground pond, it makes for easy viewing of your Koi. It even has a side view window!

Do they have any predators?

There are many animals that will target Koi for a meal, these are the most common:
  • Mink
  • Blue Herons
  • Raccoons
  • Osprey
  • Eagles
  • Cormorants
  • Green Herons
If a Koi is released into a natural pond, anything that will target a docile fish will go after a Koi!

Here are a few ways to deter predators:
  • Build a pond with steep walls (usually requiring poured concrete). Steep walls won't completely stop predators from coming to your pond, but it will keep them from going in it (except for mink, they swim).
  • String up high-tensile fishing wire around your pond, until the predators go away. Animals will have a hard time seeing the fishing line, so they will get deterred from going into your pond.
  • Put up fencing, regular or electrical around the pond. Electrical fencing works great against mink.
  • Get a scarecrow, they have a motion sensor that, when activated, will shoot a stream of water and will scare animals away.

How big will an average butterfly koi get? - Moe

Butterfly Koi
The average Butterfly Koi will grow to be about 15 to 20 inches long.

Koi Missing Scales

I have a couple of my Koi with ulcers, I have them in a 200 gallon tank and have been treating them. The larger koi (2 lbs) jumped out and was out of the tank a while. I got him back in and he seems to be doing ok, but lost a few scales. I am feeding them antibiotics in their food, is there anything I can do and should I worry about the missing scales. - Mike

You shouldn't really need to worry about the missing scales, they will grow back. Koi can live without them. Just keep an eye on the damaged areas, make sure they don't get an infection.


I have had my Koi for 3 years with no problem, since putting in air stones 2 days ago, I have had 3 Koi jump out! The air stones are round the edge, are the koi jumping through the bubbles and out of the pond??? - Del

They probably are, Koi like to play in air bubbles. Is it possible to move the air stone to a different location? Can you raise the air stone in the pond? Experiment to see if a different location will curb this jumping behavior.

Cloudy Tank Water

My Koi tank became cloudy overnight. What do you think caused that? - James

Your Koi could have stirred up some waste or sediment at the bottom of the tank.

If you are using activated carbon to filter your water, it could be all used up. It won't be filtering your water, so ammonia is building up in it, giving it a cloudy appearance.

Sunday, August 16, 2009


Doitsu Koi
Hi, Do Koi's scales can regenerate? Do Koi species without scales exist? - Stone

If damaged, by physical trauma and/or an ulcer, a Koi's scales will grow back. It takes about a year for a scale completely return. Sometimes the color will be duller than it was before the Koi lost the scale.

There are scaleless Koi. These are referred to as Doitsugoi. The regular colorful Koi were cross-breed with a European variety of carp that is scaleless in the early 20th century.

What causes Koi to jump? - Donna

Koi can jump if they are spooked, eating bugs on the surface of the water, spawning or if they have a parasite that is bothering them.

Should I salt pond?

Should I use salt in my Koi pool on a regular basis? - M Edwards

You can have a little amount of salt to help with their slime coat and osmoregulation. Don't add any if you have aquatic plants in the pond, salt will kill them. Remember to test your salt level if you are adding it on a regular basis.


I heard that a certain type of Koi could help in keeping the others calmer, what type would that be? -Jacquie

Usually larger Koi are calmer. Young Koi tend to be more on edge. Koi are a schooling fish, they are calmer when they are in a larger group.

How many 50cm Koi carp can I fit in my pond? - Alex

As a rule of thumb, figure about 500 gallons per fish. For example, if your pond is about 2500 gallons, then you can have about 5 Koi in it.

A Koi Bowl

A nice Koi swimming around in a blue bowl at a Japanese breeder.


A two-step Kohaku swimming around in a measuring tub.

Saturday, August 15, 2009

Giant Koi Carp

Here's a story that the BBC did on Mamasan. The average price of the Koi they were moving is $100,000.00.

Koi Fish Swimming in Nagoya

Koi swimming in a pond in Nagoya, Japan.

Osmoregulatory System

What is a Koi's "osmoregulatory system"? - Anna

It regulates the amount of water that's in a Koi. It involves the kidneys, the gills and the anus. When a Koi has too much water in its system, after it's absorbed through the gills, the kidneys expel some of it.

If a Koi gets sick enough for the kidneys to fail, it loses its ability to expel excess water, so it gets a condition called dropsy.



When a Koi gets dropsy, it will swell up, sometimes so much that the scales "pine cone" outwards.

Goldfish Bowl

My friend has 2 goldfish(gf) and 1 Koi all just a little over an inch long,possible 2 inches,but not quite,and she keeps them in a small goldfish bowl, is flat on the front and back. Almost a foot at the widest point and about a foot tall, I think that this isn't the best idea for them, is it? Please, I need all the info I can get, also, should i feed my gf and Koi gf flakes or Koi pellets or both??? - Anna

They would prefer to be in a big pond outside. They are small enough to fit in the bowl now, but they will grow. Make sure that the water quality stays good and they will be happy for now.

Surface Flapping

I have about 20 Koi and all appear healthy. One however is head down by the surface flapping its tail continuously. Is this part of mating or do you think it could be ill. - Paul

It sounds like your Koi has a swim bladder problem. Koi use their swim bladders to maintain buoyancy and for balance. It can get damaged by physical trauma or by an infection. Some Koi never do fully heal and have problems the rest of their lives.

Here is a video clip of someone that had a Cichlid with a swim bladder problem and they used a small piece of styrofoam to act as an artificial one. I don't know whether or not if this would work for a Koi.

Here's it after they got the correct buoyancy:

Budo Goromo

I recently bought a Budo Goromo with beautiful white skin. When it had been in my pond for a while, the white on the top of the fish has gone a smutty color. All water parameters are good. I also got a Gin Rin Ochiba which has a lovely silver and ginger color in a blue tank, but soon after putting it in the pond with a black liner, its just a dark uninspiring color. The Koi dealer where I bought it from said it was the lovely bright color when he bought it but it jumped out of a bowl when he was showing it to some one and had lost its color since then. However I know it can be the surroundings so i wonder if it will stay the dull colors now. - Jackie

Hard Water

I'm guessing that you have hard water. It will cause a Koi with white on it (like your Goromo) to get dark "smutty" colors on it. It will also cause your Ochiba to get dark. There's not much you can do to combat this other than move to a different area or bring in water from a different area.

Hand Feeding Jumbo Koi

Check out these jumbo Koi being hand fed!

Friday, August 14, 2009

Tiny Baby Koi

In this video, tiny baby Koi are swimming around in a pond.

What kind of food does a Koi eat? - Edward

During the summer, a Koi will eat a high protein food. During the spring and fall when the water temperature is above 50 degrees Fahrenheit, Koi will eat a food with a wheat germ base. When the water is below 50 degrees Fahrenheit, Koi won't eat at all. For more information, check out

What can kill big fish? - Sam

There are 3 types of things that can kill a big fish:
  • Environment
  • Disease
  • Physical Harm


The pond that a Koi lives in can be harmful if:
  • There is poor filtration and Ammonia or Nitrite builds up in the water.
  • The water temperature fluctuates more than 20 degrees in a very short period of time.
  • The pH fluctuates rapidly, or even crashes.
  • The oxygen level drops, due to poor aereation.
  • There are chemicals that are harmful to fish in the source water, ie: chlorine.


There are four types of afflictions that Koi can get:
  • Parasite Infestation
  • Bacterial Infection
  • Viruses
  • Fungus

Physical Harm

Things that can cause physical harm include:
  • Humans (rough handling)
  • Predators
  • Nets
  • Sharp rocks in the pond

How big of a fish can a cat steal?

This video demonstrates the maximum size of a fish that a cat can carry away.


Why do Koi hang around the water fall? - Eric

Koi like to hang around the waterfall because there is a high amount of dissolved oxygen in the water around it. The agitation as it crashes against the rocks adds oxygen to it.

Koi Gestation Period

What is the gestation period of a Koi? -Hawkilittle

The gestation period is this: nada, zip, zilch, zero!

Koi lay eggs, they don't carry their young to term. It does take about half a week for them to emerge from the eggs once they are spawned.

Murky Water

Murky water in a Koi pond is caused by a number of things:
  • Poor filtration or no filtration at all.
  • Runoff from rain going into the pond along with fertilizers it has picked up off the ground.
  • Overstocking, too many fish or other aquatic animals in the pond.
  • Over feeding your fish, the more you feed, the more waste the fish will produce, usually resulting in green water algae.
  • Source water, some unfiltered well water will have a large amount of dissolved sediments, which will give the water a cloudy appearance.

There are a couple of fixes for murky water:
  • Do water changes. (A temporary fix.)
  • Increase filtration to meet your pond's needs. (A permanent fix.)

Koi Hiding


It was probably your husband digging with an auger that freaked out your Koi. The vibrations from the excavation will have that effect. When you do an excavation near the pond, it is best to do it with manual labor, since it is much quieter.

My fish appear to be laying on their side. Why? -Mac

It could be an environmental or a disease issue. Check your water parameters to rule out the first issue. If it is a disease issue, consult a fish health book or a veterinarian.

Giant Goldfish

Folkstone, England
April 2008
This is "Goldie" the goldfish. He lives with 83 year old Ada Shaw. Goldie looks like any normal goldfish, apart from the fact that he nearly weighs over 2 ponds and is 15.7 inches long. And although goldfish rarely live beyond the age of ten, Goldie is now 15 years old. Marine biologists have been astounded by Goldie's size, although, he is not the largest reported goldfish in the world.

Tuesday, August 11, 2009