Goldfish

Goldfish like a tank with plenty of swimming room and are not particularly fussed about the presence or absence of decorations. A 30 gallon aquarium with gravel and few river rocks is recommended. You should never keep your goldfish in a bowl or other small container.

Making partial water changes on a weekly basis is the best way to keep your fish healthy, use an aquarium siphon hose to vacuum your gravel, remove leftover food, fish waste, and other organic material.

Goldfish are one of the hardiest of all types of fish, and are able to withstand a wide range of water conditions. However, the ideal pH is neutral to slightly alkaline (around 7.5), moderate hardness, and a temperature of between 60°F (15°C) and 75°F (24°C).

Fancy goldfish, need a tank free of active or aggressive fishes, they require optimum water conditions to prevent fin damage and deterioration. They are best maintained at around 65°F (18°C); they may be susceptible to fungal infections and fin rot if kept at low temperatures for prolonged periods. At higher temperatures the water should be kept well-aerated. Goldfish can tolerate the temperature itself quite well, but may suffer due to lack of oxygen.

Goldfish are diggers and will scatter the fine sand onto leaves, injuring thin and less hardy plants, particularly fine-leaved varieties. They often dig in the gravel and can uproot plants or damage their stems. Plants grafted onto rocks or wood (e.g. anubias, java fern) are good choices.

Goldfish are omnivorous and do not require special diet as tropical fish, however you should buy food made specifically for goldfish, because their nutritional needs are not the same as those of other fishes.

Foods designed for goldfish are usually lower in protein and fat than tropical foods, and made with a fairly high content of vegetable matter. It is generally recommended not to give goldfish too much protein, as this can lead to constipation and intestinal problems. In fancy varieties a higher level of protein is desirable as this encourages the development of the fleshy head growths in Oranda and lionhead/ranchu varieties.

If you wish to grow your goldfish a higher protein diet will also result in a faster growth rate. Where goldfish are kept in small or unfiltered aquariums, it is not recommended to give high protein food.

To avoid dietary problems, it is a good idea to include shrimp-based frozen foods and vegetable-based foods as a supplement. Frozen shrimp is also good for promoting the red-gold coloration of goldfish. Flakes or granules are suitable for small goldfish, for larger fish, pellets are usually more economical.

Never give your goldfish more food than they can eat in a few minutes. Leftover food decomposes and pollutes the tank. If food remains uneaten, remove it. Feeding your goldfish a small amount at several times during the day is preferable to feeding one big meal.