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.