Our knowledge base on koi has been growing for the last ten years and, indeed, is still expanding, although this is compared to what is actually the oldest fish hobby known, with knowledge stretching back a century or more!
Our show pond houses over two hundred koi ranging from 15cms to 85cms and displaying many of the wonderful colour combinations that make this breed of fish such a popular choice. In addition, there are some thirty Grass carp also on display there all of which gives a wonderful opportunity to see how magnificent a koi pond can be. For those who like the statistics, the show pond holds 183,000 litres of water and runs on seven pumps ranging from 0.75KW to 1.5KW together with various types of filtration and aeration equipment.
But if you don't have that much space, don't despair - outdoor koi ponds don't have to be enormous to provide an eye-catching and soothing garden feature! Raising these fish can be a fascinating and relaxing hobby. For the avid enthusiast, there are koi shows in which specimens compete according to their size and class.
We import new stock of different grades and sizes every six to eight weeks, so there is always a wide range from which to make a selection.
General information on koi Koi, or Nishikigoi, are the national fish of Japan. Nishiki describes a colorful fish in Japanese, and Goiro Koi means carp, so Nishikigoi can be translated as 'colourful carp'.
The species are thought to have originated in the Middle Eastern region now known as Iran, from a fish called Magoi, the common carp. Over a thousand years ago, magoi were widely traded as a staple food source, exported to Japan, China, and Western Europe.
Koi were first bred in Japan in the 1820s, in the town of Ojiya, in the Niigata prefecture. While they were still being bred for food, these brown fish occasionally produced red and blue mutations. Through selective breeding, the red and white variety - recognizable as the modern ornamental koi - was eventually perfected in 1870.
More than 100 colour differentials, each of which has its own name, have been bred from this single species of fish, including a glossy-scaled variety in Germany now known as the 'mirror' or 'German' carp. Koi with more than one colour are unique inasmuch as no two ever look exactly alike.
Many koi are rated by breeders as 'high-quality'. These come from some of the top breeders in Japan, and are bred from the finest bloodlines of show champions. The high-quality rating is the result of breeders evaluating physical size, physical characteristics, patterns, colors, and overall behaviour/presence.
Today, koi are bred in many countries. Due to the popularity of the hobby, and rivalry among breeders, the debate over which characteristics constitute a champion koi is not likely to be settled any time soon. To do so would spoil some of the fun! What is undoubtedly true, however, is that they are bred for the best characteristics from proven bloodlines. The price varies with area of origin, size, variety - and often demand. The shape, color, and skin quality of any individual fish can vary greatly as it grows to maturity, and the care and diet it receives will make a huge difference.
Whether the one or two year old fish selected thrives depends on the quality of its care, and on a host of variables over which only nature herself has control.
Koi are commonly evaluated by breeders and enthusiasts on characteristics in four categories:
* Size - admittedly, big koi do make a great impression. In competitions, bigger is usually thought to be better. Large size also matters because it means the fish has matured, theoretically reaching its full potential, but not all fish peak at full growth. There are early and late bloomers.
* Shape and volume are also considered when evaluating size. Ideally, the head, shoulders, mid-section, and tail, as well as pectoral fins, will be symmetrical. Other features - eyes, mouth - will have no deformities. It is the female that wins the majority of the shows as its body shape usually meets the judging requirements better.
* Pattern - koi patterns are rich and varied. Look for fish with pattern edges that are sharp and distinct. The skin should have no blemishes or dirty marks. Scales should be uniform.
* Colour - whether all white, all black, or richly patterned, the ideal color will be deep, intense, and uniform. Color can change greatly depending upon stress, water conditions, diet, and the age of the fish. During the summer months, warm water may cause colors to fade. You can make adjustments to minimize these changes.
* Presence - with observation, you will come to recognize differences in the personality and behavior of your koi. In side-by-side comparisons, one fish will distinguish itself as more healthy and vital than another. Of course, these observations are subjective, and are both the fun and controversy behind koi keeping and judging.
Fortunately, the majority of enthusiasts recognize that the health and beauty of their fish are the things that really matter. We recommend that you let your own eyes judge a fish, not someone else's.
While Koi can live longer than 200 years, their typical lifespan is 25 to 35 years. They get along well with goldfish or other tropical fish - as long as the other fish aren't aggressive or small enough to eat! Koi can be kept in aquaria as well as ponds, though the former need good filtration (one using carbon is recommended) and aeration systems.
Care and feeding: The ideal set up for koi is a pond of at least 1000 gallons/3800 litres with a fine gravel substrate, rocks and hearty plants. Koi like to eat the roots of plants and will dig to get to them, so be sure to anchor and protect plants by placing large rocks around their bases. Also, provide adequate filtration to maintain proper water conditions. Feed koi a quality pellet or flake food with a protein content that does not exceed 30%.
There are many factors to consider when feeding your Koi:
* Filter size
* Pond size
* Filter type and amount of time available to clean it
* How many koi you have in your pond
* What season of the year it is
Most people generally feed their koi two to five times a day. If you feed them around two to three times a day, they will grow slower or even stay around the same size. If you feed them three to five times a day, they will grow fast and reach their maximum size sooner. While koi can go without food for up to ten days and experience no ill effects, a regular feeding regime is less stressful for the fish.
You do have to watch how much you feed your koi, however, as you don't want to overload your biological filter. If that happens, chances are your pond will have an ammonia spike and that could possibly hurt or kill your fish. Over-feeding your koi can harm them too. They can get obese and then suffer from related health problems.
Also, the more you feed your koi, the more waste they will excrete. You'll need some way to remove the waste, or it will build up on the bottom of your pond. A good way to remove the fish waste is to install bottom drains and have them flow into your filter. You'll also need to take time each week to clean the filters, otherwise, the waste will build up in them and the water will start channeling through the filter material.
If you have a large number of koi, you'll need a big pond and a big filter if you plan on feeding them a lot and growing them out. Most koi usually grow to a couple feet in length, but if you have one with a good bloodline, it could grow up to 3'/1m long. Summertime is the grow-out period for these fish. In a natural environment, a koi will eat as much as it can during the summer in order build up fat to live on in the winter when food in scarce. You should feed your koi a food that is high in protein during the summer to boost their growth rates.
In the autumn, when your pond temperature drops below 60°F/15.5°C, you should start feeding your koi a food that is high in wheatgerm to help clean out their digestive system. When the water temperature starts dropping below 50°F/10°C, you should stop feeding them altogether. When the water temperature gets that cold, the koi digestive system stops and any food that is left in the fish will start to rot its digestive tract.
In the winter, koi do not eat at all. Their metabolism slows down to a crawl, so they only need their body fat to live on during the cold months. In the spring, their metabolism will just be starting up, so it is a good idea to feed them an easily digestible food that is high in wheatgerm again. You can start feeding them once the water temperature in your pond is constantly above 50°F/10°C. A good way to tell when to start feeding your koi is by looking at the sides of you pond to see if they have been nibbling at the algae that grows on it. Start by feeding them once a day, and then gradually increase to the amount to that which you will feed them during the summer. When the water temperature is constantly about 60°F/15.5°C, you can start feeding your koi food that is high in protein.
A good koi food will have complete proteins and also stabilized vitamin C in it. (Stabilized vitamin C lasts for months before it breaks down, while regular vitamin C has a maximum shelf life of ninety days.)
Koi are omnivorous, so they can eat a variety of things, including fruit, as a treat. They love oranges, grapefruit, lemons, watermelons, bread, earthworms, grubs and many other fruits and vegetables. Fruit is a good thing to feed your Koi because it provides a fresh source of vitamins and minerals. It is also entertaining to watch your Koi swarm around the fruit and try to eat it. Be sure to wash the fruit very well before you put it into a pond, as there could be pesticides or chemicals on the skin. If you do feed them treats once in a while, be sure to cut everything (with the exception of oranges and grapefruits which can be halved) in small pieces so your fish will be able to eat them easily.
Here are the best fruits to feed your Koi and how to do it:
* Oranges and lemons - these are a great source of vitamin C. Oranges can be halved or quartered, and then put directly into the pond. Koi will swim behind the orange as a group so that they can each get a nibble of the pulp, but will not eat the skin, so this must later be removed from the pond.
* Watermelon - is a good fruit to feed Koi too. It should be cut into 2-3"/5-7.5cm pieces so that it can be eaten easily. Try to remove most, if not all, of the seeds, for they are not very easily digested by the fish and are going to be difficult to clean out of your pond. Feeding your koi fresh fruit is very good for them. Vitamins and minerals in manufactured koi food tend to break down after a couple of months. Feeding your fish fresh fruit is a great guarantee that they are getting all of their nutrient and vitamin requirements.
Koi Health: Koi can withstand a wide range of temperatures; however sudden changes are not good for them. They can survive under the ice in extreme cold as long as the water does not freeze solid. Koi will not move around or eat much if the pond water is very cold.
Some individual fish just inexplicably die, but overall, koi are remarkably hardy and healthy creatures - much more so than goldfish or tropical fish. Chlorine or chloramines in city water and in windblown insecticides, however, are very dangerous to them. Smaller koi have a much higher mortality rate than larger ones and are more susceptible to diseases and changes in the environment.
Breeding: Koi are not live bearers but lay thousands of eggs in a single breeding. Koi must be at least three to four years old and of sufficient size before they will breed and require special water conditions and environment for the process. The eggs and baby koi should be separated from the adults or they will more than likely be eaten! Babies hatch in about three to seven days depending on the weather, but their survival rate is generally less than 50%.
Care of koi - do's and don'ts
* Feed your fish once or twice a day at least in spring and autumn and two to five times a day in summer.
* Keep your pond aerated and filtered twenty-four hours a day.
* Keep the bottom of your pond clean of debris.
* Periodically test your pond water (pH, ammonia, etc.) especially after adding fresh water.
* Watch carefully for anchor worms, lice and other parasites. Medicate with Dylex or equivalent every three months control parasites.
* Use a chlorine remover whenever adding fresh tap water. Most areas have chlorine in their tap water.
* Have medication and chlorine remover on hand for emergencies.
* Have a spare tank or aquarium for use as a hospital to treat sick or injured koi. Remember to aerate and filter 'hospital tanks'.
* Periodically clean the filter. Most filters should be cleaned at least twice a year even though the water looks clear. There is no such thing as a filter that never needs to be cleaned!
* Change or add new water periodically (about every three to four weeks) if your pond does not have an overflow for fresh water.
* Construct your pond so that water level is at least 18'/46cm deep.
* Shade the pond (at least 92% shade) to inhibit algae growth, promote and maintain colour of your koi, and keep water temperature cooler.
* After transporting koi, float the bag (unopened) in the pond for about thirty to forty-five minutes to allow the temperature inside and outside the bag to equalize before releasing the fish. When transporting koi to an aquarium or after a long trip, float the bag for at least an hour before releasing the fish.
* Always be careful when netting or handling your koi. Removing the protective slime from the body can lead to fungus or bacterial infections.
* Know the capacity of your pond. Length x width x depth (in feet) x 7.5 equals total gallons of water. (If you want to convert to litres, one gallon equals 3.785 litres.)
* Keep a spare air pump or water pump on hand for emergencies.
* Remember that stress is a major cause of koi deaths. Stress may result from such things as changes in pond conditions, over-handling, and over-medication.
* Feed your fish in winter.
* Change all the water in the pond at once unless absolutely necessary. Sudden water temperature changes may adversely affect your koi.
* Over-medicate! Use correct dosage or under-medicate if you are unsure.
* Overcrowd the pond! Remember your koi will require more oxygen and more room as they grow larger.
* Keep the water level of your pond too close to the top edge of your pond as fish may jump out or predators may catch them. Allow at least 6"/15cm clearance.
* Use any insecticide sprays, powders, or pellets near the pond. Also, do not use fertilizers on pond plants.
* Feed your koi if your pump stops working. Koi will use more oxygen if they are fed.
Pond design, construction and maintenance
There are some important points to consider when designing and constructing a Japanese koi pond yourself or with the help of professional koi pond builder.
Koi pond size and maintenance: While it is said that for the size of a koi pond the larger the better, if it is extremely large, maintenance and costs (total cost of upkeep including pump purchase and replacement, water treatments required, electricity cost, and the ability to monitor the wellbeing of your fish and net them out when required) then become an issue. For example, a koi pond larger than 20' x 12'/6.3 x 3m can become difficult to manage. It all depends on the resources you have for your koi fish care and maintenance.
- Pond depth: According to most koi experts, your pond depth should be 6'/2m. If you have a smaller pond, the minimum depth should be 4½-5'/1.5-1.75m, but deeper is better. The more shallow depths should not be used in areas where freezing over can occur in winter leading to concerns over the survival of fish.
Japanese koi pond construction: Because koi ponds require digging out part of the garden, it's a job that will probably require help, whether you're going to build a koi pond yourself, or hire a professional. You'll need sound advice and information from your builder and/or council that there are no major plumbing, sewerage or electrical lines in the area where you're intending to dig and build.
You also need to consider the type of koi pond liner you intend to use. The lining of the pond is usually in the form of a butyl liner or fibreglass. Butyl liners can be attempted by hobbyists, but fibreglass construction is generally best done by experts. As there are many different types of liners, do check that the material is safe for koi, and ensure that it is not toxic to the pond environment.
Koi pond design: Be aware that a well designed koi fish pond will help with proper maintenance of your koi fish. For example, a sloped base that leads to the bottom drains helps with drainage. Also vertical walls increase pond volume as well as reducing the chances of predators getting to the fish. If you're using a plastic lining, then you'll want to avoid sharp folds and corners to prevent breakage of the lining.
There are many good koi pond designs available, and whichever you choose, or if you modify it, always ensure that you know the actual volume in your pond, both at the design stage as well as during construction (in case it changes). This is important to enable you to calculate accurately the amount of product to use as water treatments when needed in the future.
Before considering a koi pond for the garden, always remember the safety aspects. If you have small children, or you have small children as neighbours who have access to your garden, then koi ponds may not be a safe option.