Goldfish require little care if given the attention they need. They are an easy, delightful pet to keep. The variety of bowls and aquariums available today can provide a suitable environment for the goldfish and will make attractive additions to your home. The most common goldfish available today is the comet goldfish, named after the comet shape of its tail. Other common types of goldfish include the Fantails, Calicos and Black Moores. These are similar in shape and show the same distinctive three part tail. Other types of goldfish show many varied and unique shapes. Celestials (whose eyes face upwards), Orandas (who have a distinctive hood on their heads), Bubble Eyes and Sarassa Fantails are just a few of the more exotic goldfish available today.
The most common place goldfish are kept is in the goldfish bowl. Goldfish require a larger amount of space per fish than tropicals and should be kept in the largest bowl you can get. The best rule of thumb is to keep one goldfish for each gallon of water. Goldfish bowls come in a variety of shapes and sizes. Many of these bowls are rectangular in shape while others are “drum” shaped. The surface area of the bowl is where the carbon dioxide produced by the fish is exchanged for the oxygen in the air. For this reason, it is best to fill the drum shaped bowl only 3/4 of the way, leaving as large a surface area as possible. Many people have difficulty in keeping the water clear even though the bowl is cleaned and the water dechlorinated on a regular basis. Goldfish are considered to be a cold water fish, meaning they do best in cool water where there is a larger amount of available oxygen. Since the goldfish use so much oxygen and the water is warm, bacteria develop quickly, the water becomes cloudy and the available oxygen is depleted. You can tell when the oxygen level is low when your goldfish are gasping at the surface of the water. One means of solving this problem of cloudy water is to keep the bowl in a cool location where the temperature will remain relatively constant. Goldfish bowls can become cloudy due to overcrowding. Too many fish in the bowl will exhaust the available oxygen very quickly. The extra foods and waste produced by the fish will also increase the levels of bacteria creating cloudy water. It is better to keep one goldfish per gallon of water than to provide him with a companion. Overfeeding is another reason goldfish bowls will become cloudy. You can avoid this by feeding your fish very small amounts of food often, rather than one or two large meals per day. This way uneaten food will not cloud the water. The water conditions can be improved with a pump and filter designed for goldfish bowls. The increased movement at the surface of the bowl allows for faster exchanges of carbon dioxide and oxygen and the water is filtered to help eliminate some bacteria.
Of course, goldfish can be kept in an aquarium. Be careful to keep the number of goldfish at a minimum since overcrowding can cause problems; 1 to 2 fish per gallon of water is recommended. Provide filtration in the form of a corner filter, an under gravel filter, a sponge filter or an outside power filter. The aquarium can be lit using an incandescent or fluorescent reflector. If you use an incandescent reflector, remember that it will produce heat and should only be on about 4 hours per day. Gravel can be used for decorative purposes, a means of providing some additional filtration and as an anchor for plants. Real or artificial plants can be used. Goldfish will eat certain types of live plants.
Unlike tropical fish, goldfish are considered cold water fish, and prefer water temperatures that are cooler than most tropicals require. This is one reason that goldfish are not recommended as additions to the warmer community tropical fish tank, since they use more oxygen per fish than do the tropicals. When goldfish are kept in bowls, water changes are necessary. Make sure that the new water has been dechlorinated and is about the same temperature as the water the goldfish was in before the change. Keep the bowl in a location where dust and kitchen greases cannot coat the surface, causing a oxygen supply problem. In the filtered aquarium, only partial water changes are necessary. Every week or so, remove about one-quarter to one-third of the water from the tank. An aquarium siphon works best because it will remove the water from the bottom of the aquarium where it is most dirty and also clean the debris from the gravel. As with goldfish bowls, the new water should be dechlorinated and be approximately the same temperature as the water that was removed.
The dietary requirements of goldfish are simple. Keep in mind that the goldfish is primarily a herbivore who prefers plant foods over animal foods. Basic goldfish flakes are an excellent place to begin, but should be supplemented with a variety of other foods. Conditioning (vegetable) flakes are helpful, as is the addition of some soft live plant foods, like anacharis. They can also be fed freeze dried tubifex worms and pelleted type foods. Feed the goldfish only the amount of food they can consume in about 5 minutes. Some experimentation might be necessary, but you will be rewarded by having a clearer bowl or aquarium.
Goldfish can suffer the same types of diseases as tropicals and can be medicated accordingly. The most common problems occur due to overcrowding. Goldfish especially are susceptible to a number of diseases that can be traced to crowded living conditions. Some signs to look for are a lack of appetite, scraping the body against the rocks or gravel, white spots the size of grains of salt or frayed fins. All these problems can be cured using medications for fish available at pet stores. A good diet, plenty of room, and proper living conditions will all help to minimize any potential problems.