Care
Goldfish have been with us for a very long time, having been bred from food fishes in China over a thousand years ago. They're one of the world's most popular pets and that does have some drawbacks for them, as they don't always get the treatment they deserve. A sociable species, goldfish should be kept in groups but these can consist of a mixture of similar varieties - just make sure that female fish aren't outnumbered by the more long-finned and lightly-built males, which chase them relentlessly during spawning.
Goldfish are a great choice for the garden pond. Hardy and long-lived, they'll happily live amongst pond plants and don't place too much of a burden on filtration, even as mature fish. When kept alongside varieties such as shubunkin and sarasa comets they'll freely interbreed, with fry showing dark colouration that protects them from predators until they grow large enough to look after themselves.
In their long history as pets, it's become common practice to keep goldfish indoors in containers that are much too small for them. As you can imagine, housing a 30cm pond fish in a bowl is not ideal and a suitable indoor aquarium should be at least 100 litres in capacity and well-filtered for young specimens. Far better alternatives are available for indoor keeping and tropical fish are far easier and a good deal less work. If your heart is set on goldfish as a pet, consider starting with small fish in a large aquarium which can then be upgraded to a spacious pond as they grow " obviously, this is only an option with pond-hardy varieties. Kept properly, these fish should live for decades, with the current record standing at 43 years.
Goldfish are hardy and adaptable fishes, but they prefer hard water whether indoors or out and soft, acidic conditions are to be avoided. To minimise the stresses of cold winter weather and hot summer days, a fishpond should be at least 60cm (2") deep in places. During the coldest weather, this area should remain undisturbed by vigorous water circulation and will be used as a refuge from extreme cold.
Goldfish have been bred into a great variety of shapes and colours and these are generally split into two categories - Fancy forms with modified body shapes and single-tailed forms. Fancy goldfish are less hardy and are considered aquarium fish, whereas their more fish-shaped kin are generally regarded as pond fish. You'll find more detailed profiles on the databank that go into the care requirements of each. In terms of the classic orange pond goldfish, short-finned fish are referred to as common goldfish and long-finned are known as comets. It's best not to mix fancy and single-tailed forms.
Feeding
Pond flakes, pond pellets, pond sticks, frozen/live foods etc. As the water temperature cools down in late Autumn, a lower protein wheatgerm-based food should be fed.
Breeding
At temperatures of 15c and above, male goldfish will start to pursue females in a spawning chase, driving them into suitable egg laying sites. Mature goldfish will breed on a regular basis in established ponds so do make occasional checks to ensure that the pond is not becoming overstocked. In larger ponds, keeping fish that will consume the goldfish eggs - such as orfe - is a natural way of keeping the population in check. Goldfish lay their eggs amongst aquatic vegetation (or on artificial spawning mops) and these usually hatch within 48-72 hours depending on water temperature. Young goldfish are brown in colour (like their ancestors) and it can take up to a year before brighter colouration becomes apparent. Some fish will remain the bronze colour of their wild ancestors and enjoy the benefits of being harder for predators such as herons to see.
