by: Nate Jamieson
While you may purchase young, small koi, like other species of creatures, they will adapt their growth and size somewhat, to the restrictions of space. Food and overall conditions in the aquarium will also affect their growth rate, with premium food being important, and overfeeding to be avoided both for the health of the fish, and the health of the tank environment.
Clean water is a must, as is good aeration. Large fish eat a lot of food and produce a lot of waste. If you have a 50-gallon tank, and several fish, you may need a filtration system whose capacity is actually over 50 gallons, in order to keep the water as clean as possible.
You might like to choose from several of the varieties of koi, for a more interesting mix of colors, but remember that koi in their natural outdoor environment, tend to have more intense color in cooler weather, so keep your tank temperature in a moderate zone. If you'd like to have males and females, ask for help from the breeder or store in sexing your purchases. Very young koi are difficult to tell apart, although young adult females tend to have a fuller, cigar type shape.
Some of the more attractive varieties of koi include:
Kohaku- White body and red pattern down the back. One of the most popular varieties for koi hobbyists.
Tashio Sanke- White body and red patterned back, with black accents
Showa Sanke- A three colored variety, having a black body, with white and red accents, although some strains have more white
Bekko, Utsuri- Body color is non-metallic black on white, yellow or red.