Nov 162011

Goldfish, Carassius

Download the care sheet (pdf)

East Asia

2-20 inches

Life Span
2-50 years


Congratulations on your new pet! The following are some basic guidelines to help your fish live a long, healthy life. Historians believe that goldfish were amongst the first fish to be domesticated in China around the 9th century. The modern goldfish is a tamed version of a gray-brown carp native to East Asia. Because of a dominant genetic mutation, some of these carp began displaying orange/yellow colors rather than their natural gray tones. The new “gold” variety became so popular, that during the Song Dynasty of China it was forbidden for anyone outside of the imperial family to keep goldfish with golden hues.

During the 17th century the goldfish was introduced to Europe and because of their popularity, quickly spread to North America. Because of selective breeding, there are many different classifications of goldfish based upon their color, body shape, eyes, and finnage. These include comets, black moors, ranchus, shubunkins, celestial eyes, and orandas.

Equipment – bowl, gravel, water conditioner, food, liquid biological bacteria, aquarium salt (optional), air pump (optional)
1) Rinse both the bowl and the gravel with regular tap water thoroughly. Do not use soap or any other chemicals. This is the last time the gravel will be cleaned.
2) Fill the bowl halfway with room temperature tap water; add the water conditioner, the liquid bacteria, and the aquarium salt. Aquarium salt, while optional, is a useful treatment for sores, infections, parasites, and functions as a precautionary measure against disease organisms as it stimulates the fish’s production of slime coating.
3) Float the bag within the bowl for about twenty minutes to acclimate the fish to room temperature.
4) After twenty minutes release the goldfish into the bowl and fill the bowl within two inches from the top.

Goldfish are omnivorous and should be fed a diverse diet for them to attain maximum growth, color, and life potential. Goldfish can be fed high carbohydrate-low protein flakes/pellets, bloodworms, brine shrimp, daphnia, tubifex worms, earthworms, peas, cucumbers, oats, cheese, beans, spinach, seaweed sheets, and anacharis. They should be fed a pinch of food twice a day. If any food remains after thirty seconds, they are being overfed; cut the amount of food in half.

Unfortunately, the volume of water is so small that toxic levels of fish/plant waste: ammonia and nitrite can quickly accumulate and become fatal. For this reason 25% water changes every other day are recommended. The following procedure is suggested.

1) Leave out a one-gallon container of water overnight, treated with water conditioner and salt.
2) Wipe down the inside of the bowl with an algae pad, if necessary.
3) Stir the gravel gently and carefully pour out 25% of the water.
4) Refill the bowl with the preconditioned, room temperature water.

Fortunately, there are microorganisms at work that convert ammonia into nitrite, and then nitrite into nitrate; each gas being less harmful than the one preceding it. However these organisms can only help the ecosystem; if water changes are neglected, the beneficial bacteria can easily become overwhelmed and the ecosystem is liable to crash.