page_title: Common goldfish
section_title: Housing
hierarchical_section_title: Common goldfish / Housing
caption_attribution_description: Español: Carassius auratus auratus boqueando en la superficie Goldfishes 11. May 2006 Photogaphed by Tiefflieger
context_page_description: The common goldfish is a breed of goldfish with no other differences from its living ancestor, the Prussian carp, other than its color and shape. Goldfish are a form of domesticated wild carp and are a close relative of koi. Most varieties of fancy goldfish were derived from this simple breed. Common goldfish come in a variety of colors including red, orange, red/white, white/black, yellow/white, blue, grey/brown/, olive green, yellow, white, and black, with the most common variation being orange, hence the name. Sometimes, the brightness, duration, and the vividness of the color may be an indication of the fish's health status.
context_section_description: It is a common practice to keep common goldfish in a small bowl, but this allows waste in the water to build up to toxic levels and does not provide enough oxygen. For every small/young goldfish, there should ideally be at least 10 to 20 US gallons (38 to 76 l; 8.3 to 16.7 imp gal) of water. A good filter, with no heater, is recommended because these fish can get larger than 12 inches (300 mm). Tank recommendations range up to 75 US gallons (280 l; 62 imp gal). It is possible to keep small goldfish in smaller tanks, but such an arrangement will be very difficult to maintain once the fish grows older. If there is concern about the fish not getting enough oxygen, particularly when it is warm, a water pump, such as a fountain pump, mini pond pump will pull the CO
  2 water from the bottom, expel it, and the surface action will oxygenate the tank or pond. Contrary to popular belief, air pumps and air stones do not oxygenate directly and rely on bubbles breaking the surface to transfer oxygen to the fish's environment. Ideally, the water pump should push 10x the volume of the tank or pond plus an extra 100lph or gph. Goldfish will die without sufficient dissolved oxygen in the water. A filter that can do at least 10x filtration is best, which means that for every 10 gallons or liters of water, the filter should be able to cycle 100 gallons or liters per hour. If the oxygen in the water runs out then the fish may die or become unconscious. It is advised to move the fish to a basin of water full of fresh water.
  Goldfish are curious fish that will quickly become bored without items or other fish to interact with.  If placed in a bare aquarium, goldfish will settle to the bottom and only move when fed or frightened by sudden jolts. However, if put in a tank with sufficient gravel, aquarium accessories or plants (real or fake) they will make themselves at home.
  Goldfish are not very territorial. However, if an aquarium is already too small for one goldfish, it will certainly be too small for two or more. Stress is not healthy for any goldfish. In a worst-case scenario, one or two fish will bully the rest to starvation. Cannibalism is usually rare (occurring maybe when a fish is dying or dead) but in cramped, stressful situations, goldfish may behave unpredictably. A disease is possible any time fish are stuck in small homes.
  When adding goldfish to a new tank it is important to place no more than two at a time. This allows helpful bacteria (which turns ammonia to nitrite and finally to nitrate) to grow. If introduced in too great a number before these bacteria grow, the goldfish will die from breathing in too much of their own untreated excrement.  Even after the development of the biological filter, it is necessary to change about 20% of the water at least one time a week, or as necessary to prevent a build-up of harmful nitrate.  The addition of live aquatic plants may reduce the number of times per month one will have to perform water changes, but only if the plants are growing (they will uptake nitrate as a source of nitrogen). 
  But it is also recommended if the needs are required, To never remove all of the water out of an established tank. Never do a water change over 90%, the remaining 10% of water will help maintain the waters cycle and the remaining good bacteria will soon reestablish in the tank.
  A good tip when doing a water changes is not to clean the filters at the same time (filters also hold a good amount of the good stuff as well), instead to wait 2 days after a water change to clean the filters out to keep a healthy constant balance.
  Common goldfish can be kept in water gardens or outdoor ponds throughout the year. Outdoor ponds have similar care requirement as indoor tanks with some notable exceptions such as amount of sunlight, natural and artificial environment pollution (i.e. dead leaves, debris, runoff), algae, selection of pond mates (i.e. algae eaters, frogs, etc.). Outdoor ponds tend to become miniature aquatic ecosystems, attracting various animals and plants (see water gardens for more information). In hot
caption: Common goldfish in a pond
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