About the Goldfish
Species Type: Freshwater Fish
Care Level: Moderate. May tolerate only a narrow range of water parameters, have specific dietary requirements including frozen or even live foods, may have behaviors that severely limit potential tankmates or may require a specialized aquarium setup.
Origin: Coldwater streams in ancient China.
Compatibility/Temperament: While this may be case to case basis, it is NOT generally recommended to combine feistier variants with the much slower variants such as pearlscales, bubble eyes, celestials and tosakins. Fantails and ryukins are known to get along quite well with singletails. Bubble eyes, celestials and tosakins are best kept by themselves, whereas orandas, black moors/telescopes/demekins, ranchus, lionheads and many other fancy variants not mentioned may be kept together with minimal issues.
Goldfish have been kept in China for a thousand years and have traditionally been kept in bowls however the use of bowls has been largely discouraged mainly due to their messy lifestyle. Goldfish search for food relentlessly and will simply excrete too much wastes which can cause quite a strain on most filtration systems.
The wild forms are dull brown in color although the incoming years of breeding resulted in many colorations such as orange, red, black and white. Several varieties are widely available including celestial, telescopic, bubble-eye, oranda and ryukin. Some lack the dorsal fin whereas others have extremely long caudal fins which in most cases rather impair the goldfish's ability to swim.
They are coldwater fish therefore requiring lower temperatures than most freshwater fish. Heaters are not often recommended although they are often used to simply stabilize the temperature preventing extreme changes which can kill the fish. Goldfish are not fussy with water conditions and will adapt quite well to various water conditions.
Due to the size of goldfish with fancy goldfish reaching 8 inches at most whereas comets and shubunkins are possibly even larger, it is best recommended that they be kept in a very large aquarium or pond with very powerful filtration systems (not counting the currents, of course, which the goldfish will certainly not tolerate). Ten gallons per fish is often recommended when keeping them. 30 gallons is the recommended minimum tank size for fancy goldfish. Comets and shubunkins on the other hand will require a 55 gallons for a pair alone.
Breeding is quite easy and will naturally happen in the pond rather than the aquaria. There must be a period of cold temperatures to stimulate winter before they spawn. The warming of the temperature after a few months of winterizing stimulates spawning. Males have white tubercles on their gills whereas females should appear rounder in body shape during breeding season. A sure way to tell is to look at the vent of an adult goldfish. The females have a round white or clear bump on the vent while the males' vents are concave. (like an inny or outty in human bellybuttons)
Goldfish are not fussy with foods and will appreciate nevertheless almost everything provided. They should not, on the other hand, be kept in tanks full of plants unless you don't mind if the fish gobble them up. Foods for goldfish should not consist mostly of protein. This will cause an excess of ammonia production during the digestion process. They eat all foods including pellets, flakes, and alive foods.The more exotic varieties of goldfish should not be fed dry foods without it being soaked in water first. Many goldfish become ill with swim bladder disease because the food is of low quality or too dry. Goldfish also need to have a filter or they will die.
Singletails: 12-18 inches. Shubunkins tend to be smaller however.
Fancies: In general, they can reach 8-10 inches in length although they are bulky rather than elongated. Orandas, ranchus, lionheads, ryukins and fantails in rare cases can exceed 10 inches. Bruce (an oranda from China) currently holds the record of 14.6" in length.
Pearlscales tend to grow the size of a softball in some cases. Bubble eyes, celestials and some telescopes are smaller than the more commonly available varieties.
Currently, the smallest goldfish would be Siamese doll (telescope variety) at 4-5 inches however these are incredibly hard to find.
Minimum Tank Suggestion
20g per first fancy goldfish and 10g per additional fish. 55g bare minimum for at least two singletails. The bigger, the better.
Ideal water parameters for Goldfish
Ideal pH range is 7.4 and above with hardness level not on "soft" level or below. Soft acidic water will cause their slime coating to slough off and irritate them.
Temperature range for fancies: 68-78 degrees Fahrenheit.
Temperature range for singletails (comet, shubunkin, hibuna): 45-78 degrees Fahrenheit.