Pull a drum fish from the water, and you'll understand why these descriptive names fit so well: these fish emit a distinctive knock or, in the case of a croaker fish, an eerie froglike croak.
The family of drum fish includes the croaker. They are able to make these decidedly un-fishlike sounds by using a special set of muscles located near the air bladders. The freshwater types of drum fish are prized food sources, but they also make good pets. They are not territorial or aggressive, and can get along with other fish. However, they are slow feeders so if other fish are greedy, drums may starve. Mollusks are its primary food source.
Although there are many kinds of species of drums, only those from the tropical Caribbean are popular to keep in the aquarium. Water quality requirements include a pH of about 8.2, temperatures between 78 to 82 degrees Fahrenheit, and low nitrates, ammonia and nitrites.
The most famous drum is the jackknife fish (Equetus lanceolatus), a drum that is native to the western Atlantic Ocean and parts of the Caribbean. The fish is light gray and has dark bands on its body, giving the fish its distinctive jackknife appearance. It is a more sensitive species, requiring some pampering and plenty of room. It will not survive too much harassment from other fish, and regardless how hungry will not come around for a meal if it feels uncomfortable in any way. For this reason, some suggest the beginner should not start out with the jackknife fish.
The High Hat
The high hat (Equetus acuminatus), also called the cubbyu, is sometimes available. This species is black and white with a black dorsal fin. Younger fish have a long dorsal fin that shortens as the fish ages. These fish are found mainly roaming patch reefs, and the very young fry can be seen darting among the spines of sea urchins (Diadema sp.) for protection. Don't keep this species with very aggressive fish. Like its relatives, it is very timid and minds its own business. They can be kept on their own, or with others of their kind with no problems of aggression. They also require very high quality water conditions, which makes them good candidates for those who have a healthy reef tank with less aggressive species.
The Spotted Drum
The spotted drum (Equetus punctatus) is found near Bermuda, Florida, and the Bahamas to the Antilles and Brazil. They are happiest in coral reef conditions. They are generally secretive and solitary and will spend a lot of time peeking out from beneath ledges and behind rocks. They feed on crabs, shrimps and polychaeats, mainly at night. They also require very good water conditions.