Koi fish is a pond fish that cannot be grown in the home aquarium. This fish usually lives for 20 years. But they can live for 50 years if given proper care. The beginner’s guide will give information on how to keep the fish for 50 years. 

Koi Fish – Overview

Common NameKoi fish is commonly called Koi Carp or Carp fish.
Scientific NameThey are scientifically referred to as Cyprinus rubrofuscus.
Habitat or OriginThey are native to Asia and Europe. Their habitat is lakes, ponds and streams which have muddy bottoms and the flow is minimal.
Average SizeKoi fish is a really large fish which can grow up to 3 feet in length.
ColorationThe colors of Koi fishes are vibrant. Typically these fishes are silver or white in color with scales. That show luminous color which seem to change when seen from different angles. They have colorful markings which are red, orange, deep blue or black in color.
Life SpanIn the wild they live for 20 years. But when they are given proper care they can live up to 50 years.
DietThe diet of this fish includes algae, zooplanktons, seeds, plant materials, and insects. In the pond, both natural food like algae, water plants, water fleas, brine shrimps and commercial food like pellets can be given. Rice and corn can also be given to them. They can be fed twice a day.
Gender IdentificationThe female fishes are larger in size with rounder bodies than the males. The fins of the female fishes are short and rounded. They have lobed caudal fins.
BehaviorKoi fishes are active swimmers and are really friendly with each other. They swim around in a school of 5 or more in a perfect sync. They also show off their colors without missing any opportunity. These fishes dig burrow and uproot the plants. They also eat the seeds of the plants which are below the sediments.
CompatibilityThey can be kept along with Cat fish, Perch and Bass. Minnows and killifish can also be kept. Gold fish is the most popular tank mate of this fish. Koi fishes are larger in size but do not harm or prey on other fishes. Hence they can have many fishes as their tank mates. Amphibians like frog, Salamanders and Newts can also be kept in the pond. Koi fishes can be kept together from 5 to 15 fishes in a pond.
Ideal Tank ConditionsWater garden is the best type of ecosystem for Koi. The pond should be made of concrete. The bottom of the pond should be a muddy substrate. Plants which are non invasive like water lilies, water hyacinth, pickerels, floating pond weeds, duckweeds and cattails can be kept in the pond. The size of the pond should be 250 gallons for one Koi. If they are kept in a school the pond should have at least 1000 gallons of water. The tank should be cleaned every 2 to 4 weeks.
Water ParametersThe temperature of the water should be 74 – 86 degree all the time. In winter, water heater can be set up to maintain the temperature. The pH of the water should be 6-9. This can be achieved by using crushed limestone in the pond.
BreedingBreeding can occur both naturally and through hormonal injection. When the fish is 5 years old, it become sexually mature. The male fishes can be 2-3 in number for every female. The pond temperature should be kept around 64-72 degree F. they should be given high protein diet, three times a day. Females lay egg in shallow water and the males fertilize them after they are laid. These fertilized eggs should be kept in incubation tank where they will hatch in 3 – 4 days. Fries can be reared in indoor tank and can be fed with hardboiled eggs mixed with water and live brine shrimp. Once they reach their juvenile stage they can be kept along with the adults and can be fed the same as adults.
Common DiseasesKoi fishes are susceptible to herpesvirus which is fatal. This KHV is a common disease of all the carps. The symptoms of this illness are sunken eyes, red and white lesions at the gills and difficulty in breathing. Ulcerative diseases etc., Other diseases include ich, fish lice etc. the tank can be cleaned every 2 – 4 weeks.
Approximate CostThis fish can be brought from pond suppliers or breeders for $50 to $80. Some special species are expensive which can cost $200 and range more than $1000.
What to look when buyingSince the Koi fishes are expensive, beginners can opt for less expensive ones. You can just check for the colors and the respective species that you want to buy.
Species in the MarketButterfly Koi fish, Japanese Koi fish, black and white Koi fish, Gold Koi fish and Dragon Koi fishes are the species that are available in the market.

Gallery of Koi Fish