Sunday, February 27, 2011

How to Fold an Origami Koi Fish

Follow the instructions on the video clip to find out how to fold an origami Koi fish.

Saturday, February 26, 2011

Staying at bottom of the pond

My new Kois are just staying at bottom of pond all curled up together, my question is why do they do that? When will they get active? -Aileen

Koi fish will hide at the bottom, in rocks or even in a skimmer basket when they are introduced into new surroundings.  Some people will float a couple pieces of Styrofoam on the surface to provide cover for the Koi so they will feel safer.  It can take two to four weeks for your Koi to get used to their new pond.

Koi Cam

Check out this underwater camera footage of a group of Koi swimming around their pond.

Bringing the Koi In

Well I have a Koi pond outside and there is a a very pretty koi in it. He is so pretty that I want to bring him in the house. What size tank should i get for him? He is only about 4 to 5 inches big. -Megan

You can fit in a 30 gallon tank, but he will probably grow in the future, so you may want to go with a 55 gallon one.  You can also go with a horse trough if it gets too big for an aquarium.

Hundreds of Babies

I have hundreds of baby Koi in my pond - can I keep some in an aquarium? -Mack

You most certainly can!  By putting the Koi "fry" in an aquarium, you can take extra good care of them until they reach a larger size.  When you move them from the pond, take extra care when acclimating them to the tank.  You can even go as far as using the pond water to fill up the aquarium.  Koi fry will be very sensitive to water parameter changes.

Girl or Guy Fish?

How can you tell if it's a girl fish or a guy fish? - Maria

It usually takes two years for a Koi fry to be considered a mature "adult".  Before they are adults, both male and female Koi will look almost exactly the same.  After two years, you will notice these differences:

Male Koi:

  • will be smaller
  • have a cigar shaped body
  • fins will have a triangular shape
Female Koi:
  • will be larger
  • have a blimp shaped body (they get full of eggs)
  • fins will have a rounded shape

Friday, February 25, 2011

Pond Heater

Should I put a pond heater in for my Koi fish? I live in Pennsylvania and it gets pretty cold during the winter. (10-30 degrees) - Sam

You should put a heater (also known as a de-icer) in your pond.  Your main goal is to keep a hole in the ice for gas exchange (fresh oxygen in, carbon dioxide out).  You can also put in an air stone and an air diffuser to help aerate the water.  The pond should be at least three feet deep, otherwise you should keep your Koi indoors in a winter tank.

Koi Fish Tattoo Cover

This talented artist covers an eagle tattoo with one of a mean looking Koi fish.

DO Level

We have about five large koi and have had them for a long time. We woke up this morning and they were all dead, but all the little koi and goldfish are fine. What does this mean? -Karen

It appears that the levels of DO (dissolved oxygen) in your pond water have dropped below levels that the large Koi need to survive.  Large Koi need more oxygen than small Koi, and unfortunately, they are the first ones to go when the DO levels drop.

Why did the oxygen level go down?

As temperature of water increases, the amount of oxygen it can hold decreases.  Some types of Algae in the pond will produce oxygen during the day, but at night they will strip it from the water.  Also, if you have a waterfall that aerates the water: up until last year it could have supported your fish load just fine, but this year your fish load could have increased (due to the Koi growing), so it may have not been effective at keeping the DO level up.

Add an air pump and an air stone to your pond setup to maintain the proper oxygen level in your pond at all times.  You can also find test kits that measure the DO level in the water.

Scared Fish

Its been a week since I last bought my Koi (3 to 4 inches) and I have placed them in my water feature fiberglass tank. Unfortunately, they always hide and very shy and will only come out to feed. What can I do? -Simon

Sounds like your Koi are suffering from "New Pond Syndrome".  It usually takes a Koi two to four weeks to adjust to its new surrounding.  In the meantime, it will hide until it is comfortable.

How old do koi typically live?

They usually live to be 20 to 30 years old. Several factors that determine how long a Koi will live include:

  • Overall Health
  • Pond Water Quality
  • External Stressors
  • Diet
  • Climate of the pond location

Thursday, February 24, 2011

Can Kois be kept in a tank in the house?

They will outgrow a regular fish tank, but you can construct an indoor pond to house them.  An indoor pond will provide plenty of room for the Koi to swim around in and it will allow you to view the Koi from the top down.

Koi can be kept in an indoor tank during the wintertime for a short period, but they need a larger living quarters on a permanent basis.

Missing Goldfish

Hey, we have a 4 ft deep pond and we discovered some goldfish missing. How could a raccoon get them? -Anthony

If there are any shallow areas in your pond, the raccoon could have waded in and fished out some of your goldfish.  If your pond has steep sides, it could have sat on the edge and grabbed a few.

Do Koi Entertain Themselves?

What do Koi like to do to entertain themselves, beside eating, breeding, producing wastes?  Would they play with a floating ball if i put it in the water? are they known to enjoy any type of toys? - Maurice

The only form of entertainment that Koi seem to enjoy is destroying the plants in people ponds.  That, and begging for food.

Indoor Koi Tank Temperature

What temp does the water have to be in my indoor tank? - Ron

You can keep the water at room temperature and your Koi will do fine.  Koi can live in a wide temperature range, but they are at their healthiest when the water is warm.

Wednesday, February 23, 2011

Are Koi able to be left out in ponds in freezing weather?

You can leave Koi out in ponds, but you will need to take some precautions to make sure that they will be able to survive the winter.

  1. Clean the pond out in the fall
    Leaves and fish waste will decompose during the winter time and will foul up the water.  Remove all the leaves and fish waste in the pond before winter.

  2. Keep a hole open in the ice
    A hole in the ice allows fresh oxygen to enter the water and it lets carbon dioxide escape.  If too much carbon dioxide builds up in the water, it can cause a pH crash (carbon dioxide is acidic and will use up the kh in the water.  Once all of the kh is gone, the pH drops).  You can use a horse trough heater and an air bubbler to keep the hole open.

  3. Do a regular water change
    Koi love fresh water.  Adding fresh water to the pond will also increase the kh levels so you will have a stable pH.

  4. Cover part of the pond with Styrofoam insulation
    It will help keep the pond temperature stable in the spring time when the temperature fluctuates rapidly.  Rapid temperature changes can interfere with a Koi's metabolism.

When to start feeding

We are newcomers to Koi. We purchased a house with a koi pond. We live in SC and it appears that winter is over. Should I start to feed them again?
They look hungry when we are by the pond. Can you advise me? - Lola

If I were you, I would get myself a Koi pond thermometer.  Use it to take the temperature of the pond water in the morning and in the evening.  Koi can start eating when the temperature remains above 52 degrees Fahrenheit.  Refrain from feeding them if the pond temperature drops below 52 degrees at night.

Feed them a wheat germ based Koi food until the water temperature reaches 60 degrees and then switch to a 50/50 mix of high protein Koi food and wheat germ Koi food.  After the water is above 65 degrees, feed them 100% high protein Koi food.


Will the fish only grow as large as the pond will allow them to grow?

Nope.  Koi will grow until it reaches its genetically predetermined size.  The size of the pond affects the growth rate, along with feeding, filtration and seasonal temperatures.


My Butterfly Koi looks like it is having a seizure and will not swim with the rest of the Koi and it stays on the bottom what is going on and should I be worried? - Josh

Your Koi probably has a parasite infestation.  Have a vet come out and look at the fish. The vet will also take a slime coat scraping and then will inspect it under a microscope to see what parasite(s) are on your Koi.  The vet will then go over a course of treatment with you.

What do koi fish eggs look like?

Koi fish eggs look small yellow dots, that are around a millimeter in size.  You can find them attached to the vegetation in your pond or on the pond walls.  After the gestation period, you will notice small fry swimming around in the pond.

Check out this video to see what Koi eggs look like on the vegetation in the pond:

Tuesday, February 22, 2011


What fish make good companions for Koi - Lisa

Any fish variety that is considered "docile" will do fine with the Koi in your pond.

Plecostomus are a docile fish that thrive in ponds during the summer, due to the abundance of carpet algae on the pond walls for them to eat.  They will need to be removed if the water temp drops below 65 degrees F since they are a tropical fish.

Goldfish also make good companions for Koi, but the population will need to be controlled otherwise the goldfish will keep on breeding and the water quality will go bad from being over stocked.

Remember to quarantine any fish you buy before adding it to the pond.

Any docile fish variety that is viewed from the top down will make a great addition.

Pond Size

Can I put Koi into a well filtered pond measuring 18m x 1.2m x 1.2m? -Rich

That pond size calculates to be about 6,500 gallons.  It could be wider and deeper, but it is still a good volume of water for the fish to swim in.  You can put a couple dozen Koi in your pond.

Body Structure

What is the difference between the body structure of male and female Koi carp fishes? -Geetha

Male Koi fish will have a body that is long and thin, like a cigar.  Female Koi will take on a blimp shape, since they are full of eggs.  Female Koi are usually larger than males because the many males will gang up on one female during breeding season.  You don't want the males to damage the females, so they need to be smaller.

Monday, February 21, 2011

Underwater Koi Video

A group of Koi swims around in their tank with some wonderful music.

Bug Zapper

I put a light over my pond at night so my Koi can eat the insects that fall in the water. Is this a good idea? - Davis

As long as the zapper mounted correctly so it won't fall into the water and the amount of bugs that end up in the water don't foul it up, then go right ahead.  Bugs are full of protein, vitamins and minerals (Koi find them very tasty too).


How long does it take for the Koi to fully mature? - Leanne

It takes about two years for a Koi to reach sexual maturity.  The amount of time it takes a Koi to reach its maximum growth potential depends on your location.  If you live in a warmer climate and have a large pond, a Koi will mature in six to eight years.  If you live in a colder climate, a Koi will mature in eight to ten years.

Koi Fish

Koi Fish are known to live for twenty to thirty years.  The oldest Koi fish, Hanako, was 226 years old.  The most popular varieties of Koi Fish are:
  • Kohaku (red and white)
  • Sanke (red, white and black)
  • Showa (black, red and white)
(But not necessarily in that order.)

People enjoy the interaction and colors the fish add to the pond.  The fish are tame and are often taught to eat right from your hand.

The fish can grow up to three feet in length.  The hobby originated in Japan and spread across the world around 50 years ago.  Advanced hobbyists enter their fish into shows and they compete for the most beautiful fish.

Koi Eating Water Lilies

My Koi tends to eat my leaves on the water lilies, is this a normal behavior? - Carolyn

Koi are omnivorous, they eat both plants and small aquatic animals.  Unfortunately, they find water lilies very palatable and will devour them without remorse.  The best way to prevent the Koi fish from decimating your water lilies is to cordon off an area of the pond for the plants.  You can also build a separate pond for your water lilies if you have both the room and the budget for it.


This collection of Koi swims around while being fed their pellet food. Everything is frozen this time of the year in the upper latitudes of the northern hemisphere and most of the "Koi Kichi" people are really missing their collections.

Saturday, February 19, 2011

Fin Problem

I just bought a Koi and the tail is long. We left for the day and when we returned the top of the tail is missing. Is this some type of disease? All other fish are fine. - Rob

The Koi could have broken part of his fin off.  Long fins tend to be brittle and can tear if the Koi is mishandled or if the fin catches on something in the pond.  Long fins on older Koi usually take on a ragged appearance, due to normal wear and tear.

The Koi can also have fin rot, a condition caused by a bacterial infection in the fin.  A course of antibiotics prescribed by a veterinarian or a Tricide-Neo dip will treat fin rot.

Friday, February 18, 2011

2011 San Diego Koi Show

The 2011 San Diego Koi show starts tomorrow. Koi Club of San Diego hosted one of the first Koi shows in the US. This year marks their 24th annual Koi Show. Around 3,000 Koi enthusiasts are expected to attend.

Where: Del Mar Fairgrounds, 2260 Jimmy Durante Blvd, Del Mar, CA 92014
  • February 19th: 9 am to 4 pm
  • February 20th 9 am to 3 pm

Thursday, February 17, 2011

Feeding Koi at the Japanese Friendship Garden

In this clip, we have a couple feeding the Koi at the Japanese Friendship Garden in Phoenix, AZ. The Koi love their food.

New Pond

I just bought a 5000L pond. How long I need to leave it running before I put the fish in it?

You should de-chlorinate and let the pond sit for about a week.  Depending on the type of filtration that the pond has, you may want to introduce a few small Koi at first, and then gradually add more to the pond. 

Chemical filters that use activated carbon do not require any bacteria to filter the water (the activated carbon strips Ammonia from the water).  Biological filters require the media to be colonized by Nitrifying bacteria.  Nitrifying bacteria converter Ammonia into Nitrite, and then Nitrite into Nitrate, which is harmless in low concentrations in the pond water.  Nitrifying bacteria take four to six weeks to grow so you should start the pond with a low stocking density so the water quality won't go bad.

You should add a few Koi instead of one to begin with because Koi are a schooling fish and having only one Koi in a pond will stress it out.

Tuesday, February 15, 2011

Koi Fish in Distress

I have a big Koi Pond (approximately 3500 gallons, with clear water, only six adult Koi and eight little Koi). Lately they are schooling together, and a couple of them seem to be sucking for air.  Help, any answers? -Larry

Your pond may need more aeration for your Koi fish.  If the oxygen levels in your pond are low, the largest fish (the ones that need more oxygen) with suffer first.  Adding an air pump and an air stone will help bring your oxygen levels in the pump for the Koi fish up.

Malaysian Koi Pond Harvest

In Malaysia, this is how they harvest a Koi mud pond:

Step One: Inspect the pond
Step Two: Go to karaoke bar
Step Three: ???
Step Four: Sing karaoke
Step Five (not in the video clip): Harvest mud pond

Friday, February 11, 2011

Can Koi Live in Muddy Water?

Yes they can, as long as the water quality stays good.  The water should have no Ammonia and plenty of dissolved oxygen.

In Japan, the Koi are grown in mud ponds.  The ponds are generally one to five acres in size and are lined with bentonite clay.  The Koi are placed in the ponds in the spring and, depending on their size, may going through two or three culling cycles in the summer.  In the fall, the Koi are harvested and brought to the greenhouses for sale.

Wednesday, February 9, 2011

There's a New Guide in Town

Koi Acres released a guide on how to build and maintain Koi ponds.  Check it out!