Goldfish belong to a large family of fish called Cyprinidae, which includes carp and koi. Goldfish are fairly easy to care for and are often the first fish the budding fish enthusiast acquires. Goldfish are roughly dividable into two types – ordinary goldfish with one tail, and fancy goldfish with two tails. If your fish is swimming to the top of the tank, observe it closely to determine whether the behavior is normal or an indication that something is wrong.
