Gold fish Carassius auratus was the first fish species reared and breed among the ornamental fishes. It has been in used in China, since 1000 BC, and remained there unknown to rest of the world for nearly 900 years until it was introduced in Japan, during 1603, followed by Portuguese during 1611. Since then Goldfish has seen great developments in strains, colors, size and shapes. Goldfish remains one of the most popular species in aquarium. Any hobbyists would definitely love breeding their favorite fish species and gold fish stands first. Several fish breeders in China, Japan and Europe have done numerous works in selective breeding of Gold fish resulting in the development of nearly 20 known varieties with their own specific lineage and market. However, breeding goldfish breeding is not an easy task. Unlike livebearers, such as guppies, goldfish can be relatively difficult to breed in captivity. In order to breed successfully, goldfish need their usual quality care, plenty of space, good nutrition and excellent water conditions – plus specific temperature changes to induce breeding.
Before commencing a goldfish breeding program, a suitable tank for breeding and nursery rearing should be planned. Goldfish breeding requires one main tank of 100 litre capacity, with sufficient filtering equipment, fry rearing tank of 50 litre capacity minimum, egg collectors, sponge filter and air-pump.
Brood stock can be purchased from the aquarium shop or reared in the farm; farm reared are best. Goldfish mature when they reach 1 year and hence, can be easily reared in the farm itself. Buying adult mature Gold fish may be a costly affair, depednign on the colour, scale pattern, body shape, and variety. The best alternate for farmers is to purchase young fishes with good color pattern and rear them in their respective farms. Generally, for breeding any farmer require more males than females, as this increases the chance of a successful spawning approximately at a ratio of 2:1.
During the breeding season, the following physical features develop:
|1||Males develop breeding tubercles (white pimples) on the gill covers and on the pectoral fins||No tubercle formation|
|2||Male bodies are slender||Females develop a deeper body as they fill with roe (Mass of eggs)|
|3||Vent is normal, slightly concave||Vent enlarges slightly and appears slightly out-turned|
Filtration, aquatic plants as an egg collector or happa stripes as egg collectors. The egg collectors will help to protect the eggs from their parents and will make it easier to move the newly hatched eggs into the fry tank. Once the main tank is ready with full functioning filter, adult fishes are added. The stocked brood fish are fed with good brood diet. Just before beginning the goldfish breeding program, a smaller tank for the fry is also set up. This fry tank should be about 50 litres and only filled to between six and eight inches deep, with water from the main tank.
The brood fish are fed with good protein rich diet, slowly, without abruptly changing the diet. They are slowly introduced non-pelleted feed, such as brine shrimp or live black worms. This simulates the natural springtime when goldfish like to breed and induces ovarian development in the females. The Goldfish need to be fed in small amounts three times a day. Care should be taken not to over feed the fishes as uneaten feed can spoil the water quality.
Young robust goldfish are ideal because of their high fertility and sex-drive. For a female goldfish, look for ones with large rear and pectoral areas; for males, find a large male (approximately anywhere from 4 to 6 inches) that is also a fast swimmer. Males with many small tubercles behind their heads on their gills is a sign of an ideal mate. For an ideal mix of breeders, isolate three best male and two best female goldfish.
Goldfish breed in the spring, where breeding is triggered by a change in temperature (from the cold winter to the warmer spring). To replicate this temperature change in your own goldfish breeding setup, first lower the temperature of the tank and raise the temperature of the water by 2°C per day, until it is between 20°C and 23°C. This gradual change in temperature induces natural spawning in the goldfishes.
Readiness to breed in Goldfish can be identified clearly, when males display white “tubercles" on their gills and fins and females look fatter than usual. The males also exhibit a spawning behavior of chasing the females around the tank and poking their abdomen. When the female is in full ripeness, it swims to a planted area of the tank and/or near the egg collectors and lay sticky eggs, which attach themselves to the plants and / or egg collectors. The chasing males immediately swim over eggs and releases sperm to fertilize them.
Goldfish are hungry immediately after spawning hence more often they may eat their own eggs; hence, the parents should be removed from the tank or pond as soon as spawning is complete. Alternatively, the eggs being sticky and attached to egg collectors, can be easily removed and transferred to the fry tank. The temperature of the fry tank should be similar to the main tank. Lighter colored eggs have a much greater chance of hatching, hence, dark colored eggs can be disposed and only lighter ones be transferred to the fry tank. Depending on temperature, fertilized eggs hatch within 4 to 7 days. When the eggs hatch, they usually lie gently on the tank bottom, until the yolk is fully absorbed.
Goldfish fry should not be fed straight away. For the first couple of days after hatching, the fry will lie on the bottom of the tank and survive on the yolk. Hence, they don’t need any feeding. Once the fry starts freely swimming around the tank they need to be fed as the yolk gets completed absorbed. They are still too small for fish feeds hence; they should be fed with egg yolk dissolved in water.
• Take a hardboiled egg
• Break a piece of the yolk
• Put the piece of yolk in a sealed jar of water from the fry tank
• Shake the jar until the egg mixes and the water turns cloudy
• Pour very small amounts (just a few drops) into the tank at a time and store the rest in the refrigerator for future feeding sessions
• Always using reasonably fresh egg