Fish Care - Caring for Goldfish

TetraTalk Issue 1, 2003

The goldfish is perhaps the most popular aquarium fish in the world, and is certainly the one that most first-time fishkeepers start with. Their bold colour and character has endeared them to generations of people, and they are an ideal pet for children, teaching responsibility but without the demands of a larger animal.

History of the Goldfish
The goldfish, Carassius auratus auratus , is native to China and central Asia, and exists in the wild as a natural brown/silvery fish, unlike the highly coloured varieties we are used to. Occasionally, these wild populations throw up a slightly unusual individual, for instance one that is white or orange, and it was these oddities that captured the interest of early fishkeepers. The earliest reliable records relating to goldfish being kept as pets date back to the Sung dynasty in China, in around 1000AD, although these strange colour varieties had been noted much earlier (around 300AD). The Chinese embraced these fish, and set about intensifying their colours through careful selective breeding. By the end of the 13 th century, gold, silver, red, black and mottled fish had become established. Over the subsequent centuries, the Chinese, followed by the Japanese, and then the Americans and Europeans, developed the vast array of colours and shapes that we see today.

Varieties
There are far too many varieties of goldfish to mention them all individually, but it is worth separating “fancy” from “ordinary” varieties. Fancy goldfish, such as the Black Moor or Oranda, generally have an unnatural body shape and finnage. They are ideal for indoor aquaria, but do not fair well outside, where they struggle to cope with winter temperatures. Ordinary goldfish, which include shubunkins and comets, have a more normal body shape, but the fins may still be more or less ornate. These fish can be kept indoors or outdoors.

It is better not to mix fancy and ordinary forms of goldfish, as the former tend to be overshadowed by their more agile tank mates. In addition, the body shape of some fancy goldfish can give the impression that they are mature females, ready to spawn, leaving them subject to constant harassment.

Did you know ...

•  Goldfish need the same care as other fish, and do not like being kept in unfiltered aquariums.

•  Bowls are not ideal for goldfish, and if possible you should try to provide them with a proper aquarium.

•  Goldfish can live a very long time in captivity. The oldest know goldfish was called ‘Tish', and lived for 43 years.

•  Goldfish change colour as they grow. Starting as brown fry, they then go orange after a few years, and some even go white as they get old, just like us!

•  Contrary to popular belief, goldfish are not restricted to a seven second memory, and can even associate the appearance of their owner with feeding time.

•  Goldfish can live in a greater range of temperatures than any other fish – from 0°C to 41°C (tropical fish need a temperature of 25°C).

•  Goldfish can live happily in brackish water, at salt levels up to 5ppt (parts per thousand). Normal salt water is 35ppt, and freshwater is virtually zero.

•  There is a wild form of the goldfish, Carassius auratus gibelio , from Eastern Europe, which only exists as females (males are very rare). They are “gynogenetic”, meaning that the female's eggs develop with only her genetic material. She spawns with males of other species, and their sperm merely triggers egg development, rather than contributing to the genetic make-up of the young.