Koivet.com
Koivet is a venerable, long lived koi and pond fish health site started by Dr Erik Johnson in 1994 as an off shoot of his first few websites at Mindspring.com. Now Koivet is full of information and movies and more.

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Koi, goldfish and pond fish Keeping

The Koi, goldfish and pond fish is a durable teleost physostome fish of the Cyprinid class. The Koi, goldfish and pond fish is scientifically referred to as Carrassius auratus. Koi, goldfish and pond fish occur in numerous varieties, which are described in detail in other sections of this book. As pet fish go, the Koi, goldfish and pond fish may be one of the most hardy fishes kept as an ornamental species because it can withstand temperatures as low as 33 degrees F^o and as high as the low 100’s in the peak of summer. Koi, goldfish and pond fish can withstand very poor water quality for long periods of time if they are spared any additional stress. It is clinically relevant that they are fundamentally a river fish, but can adapt to almost any body of water as long as some nominal water movement oxygenates it. As river fish, the hobbyist will find the Koi, goldfish and pond fish more energetic and active with dynamic water current and plenty of aeration. Stale still water tends to flatten their usually lusty activity level.

<graphic>As an ornament, the fish is unparalleled. There are more colors and body morphs of this species than any other ornamental fish. The Koi, goldfish and pond fish in it’s many forms may range in size from a diminutive Natkin which may be only 2 inches at breeding size, up to a twenty to twenty two inch Pond Comet. Larger still, the Koi  x Comet hybrid can lumber in just under two feet and weigh six pounds.

Finally, Koi, goldfish and pond fish can represent a human achievement on several levels. The proud owner of a beautiful Ranchu or Lionhead who wins a ribbon in a Koi, goldfish and pond fish Exhibition will cherish such a pet and derive great pleasure from the possession of such a living jewel. <graphic>The breeders in Hamamatsu City in Japan take their Ranchu so seriously, that they trace their pedigrees back many generations and provide certificates with each fish sold. They have every reason to be proud. And finally, a hobbyist may be proud of a collection of valuable and attractive fish for many years.

Housing

Koi, goldfish and pond fish may be housed in containers as small as two gallons (although performance will be very poor) all the way across the range of possibilities to lakes and pools of many thousands of gallons. Pool fish tend to be the hardiest varieties, including Comets, Shubunkins, and Sarassa Comets. These species will over-winter in North America without a problem unless the pond freezes solid. Other species trace their lineage back to truly warm water varieties such as Oranda, Ryukins, and Ranchu. These fish may survive a temperate winter in North America when left outside, but my clinical experience has been that they do this with less and less success as they mature. The more highly selected Asian carps such as those mentioned will do better at room temperature or above.

<graphic>Aquaria are the most common means of maintaining a collection of ornamental Koi, goldfish and pond fish such as we will be discussing in this book. I would like to draw your attention to the clinically relevant fact that the larger the aquarium you choose for your collection, the better your results will be. That probably bears repeating. Get the largest tank you can afford if you want the best possible results with your Koi, goldfish and pond fish.