Choosing a Goldfish

Keep in mind that all goldfish have been bred from the common goldfish, Carassius auratus. All goldfish are basically a variation on two or three body types. There are the sleeker fish, like the Comet; egg shaped goldfish, like the Pearl Scale; and egg shaped goldfish without dorsal fins, like the Ranchu. Basically, all the varieties have at one time or another been bred with all the other varieties, creating one more variety for each new fish. This may make it tempting to mix different types of goldfish in the same tank.

The only real way to keep goldfish with other goldfish is to keep the same types together in groups. For example, Comets and Bubble Eyes would not live comfortably together, because the former swim faster and tend to eat more and faster than the latter, which are delicate and need expert handling.

Like all fish, goldfish tend to pick on injured or much smaller fish, especially if the aquarium is crowded. Generally speaking, though, goldfish are not aggressive when kept with other goldfish of the same type. They do tend to be aggressive during breeding time. However, males do not fight for the right to mate with a female goldfish. Instead, male goldfish chase the females until they eventually get their chance to spawn.

When you are choosing goldfish, any good aquarium dealer will tell you that this species should not be kept with other tropical fish. You should always make sure that you do not keep goldfish with other fish.. Why? There are many reasons.

Overall, goldfish are hardier than other tropical fish. They do not require a heater in their tank, and are actually better off if the temperature gets cold for a little while. Tropical fish, for the most part, require a consistent temperature in the low 70s, while goldfish can live comfortably in the mid to low 40s. Although goldfish can certainly survive in higher temperatures, they tend to be more susceptible to disease when they are too warm.

Goldfish don't really get along with other fish, either. Depending on the variety, goldfish can be too aggressive or they can end up as the other fish's lunch. Goldfish might also become territorial when kept with some kinds of common community fish. For example, angelfish and goldfish do not get along. Kept with cichlids, such as Oscars and jack Dempseys, your goldfish is likely to be gone by morning.

Finally, given the opportunity, goldfish will grow significantly larger than many other aquarium fish. Of course, there are exceptions among the tropical fish world, including the Oscar and the Arrowana - both of which feed on small fish, including goldfish.

Goldfish are generally very active and are capable of growing quite large. The common goldfish can grow to more than a foot. The general rule is 1 inch of fish for each gallon of water your aquarium tank will hold. But you can't keep a 12 inch goldfish in a 12 gallon tank. When selecting the number of goldfish you want, be sure to keep in mind the size of your aquarium.

Overcrowding will create poor water quality and your fish will suffer. You simply cannot supply enough oxygen to accommodate an overcrowded aquarium. The idea is to create an environment that is beneficial to the fish, not to pack as many fish into as small a place as possible. The more space per goldfish, the healthier and more active they will be.