Goldfishes were first among the fishes and also the most common fishes that were kept as pets. They are popular because they are inexpensive and long lasting. They can even survive in ponds covered with ice, until they have sufficient supply of oxygen. Many types of goldfishes are available in the market. Because of selective breeding, different types of goldfishes are available which differ in color, shape, eye and fin configuration. Some of these fishes cannot survive in the wild and must be kept only in the aquarium. This is because of their attractive colors. Thanks to mixed breeding, the body of some fishes have been modified which is an obstruction in natural breeding. Such kinds of fishes are hand bred, but this procedure is very risky and has to be executed very carefully.
Goldfishes can be kept in aquarium with cold water. According to the popular perception, goldfishes should have to be kept in goldfish bowl. But what people do not realize is that the decreased water surface area provides lesser oxygen to the fishes, which can result in difficulty in respiration. The fishes also die very quickly because of ammonia or nitrite poisoning. Hence, goldfish bowls have been banned in many countries. Also goldfishes that are kept in bowls have a shorter lifespan. One medium sized goldfish need minimum of ten gallons of water. Goldfishes intoxicate the water very quickly with their feces and the chemicals released from their gills. The water should be cleaned regularly otherwise the fishes can die in a short period. The water surface area should be considered when introducing new fishes to the aquarium, because more the water surface area, more the diffused oxygen. The water can also be aerated with the help of filter or water pump. Goldfishes cannot survive sudden water temperature shifts. This usually happens in winters, when the heating is turned on.
The goldfishes shouldnt be touched because it would result in slimy coating on its body coming out, which exposes the skin to bacterial infection. This is very dangerous to the health of the fish. Goldfishes, when kept in dark will loose their color. This is because they have pigments in the cells, similar to the pigments in human, which causes it to become tan. Therefore, lights should be installed in closed rooms. A full hood can be used to provide adequate light. But if the aquarium has water less than thirty gallons, then the room lights will do the job. Also the aquarium can be placed in natural light, if it is available.
Goldfishes are opportunistic feeders, that is, they will eat whenever food is provided to them. The more the food given to them, the more the waste created. They should be given food only twice a day and the quantity must be only that much which it can finish in couple of minutes. The food should have high carbohydrate and low protein, as the fish will be unable to digest proteins well because of the lack of stomach. Other than the commercial food flakes and pellets, they can also be given bloodworms and green leafy vegetables. If the fishes are overfed, it could lead to the bursting of their intestines.
The goldfish can grow up to twenty-three inches and can weigh up to ten pounds. There are known to live for twenty years, but in captivity they live for eight years. Goldfishes although are good in aquariums, they can also be kept in ponds. The depth of the water should be more than thirty inches, so that the water doesnt freeze in winter. Plants should also be added to the pond as they will filter the water and even increase the oxygen amount in the water. Along with that, filters should also be used to the clean the pond water. Ponds are a good place to breed goldfishes. Water surface should be one square foot for each inch of fishs length.
The goldfishes kept in the aquarium and as well as in the ponds should not be mixed with tropical fishes or any other kind of fish. Since most of the goldfishes are hybrid variety, they are more prone to attacks. Some fishes not only attack the goldfishes, but also suck on their wounds.