Q. I am in the process of setting up a 10-gallon tropical fish aquarium, and am trying to find some information about bala sharks. Basically, I am concerned that the aquarium will be a little too small for a bala shark. I would like to know how big the sharks get, how much and what do they eat, and whether I can keep other small cleaner fish in the aquarium with a shark.
A. I am a little confused by your wording and reference to cleaner fish. All fish that I know of that are referred to as “cleaner fish” are saltwater cleaner wrasse fish and are incompatible with the bala shark. The so-called bala shark, scientifically known as Balantiocheilus melanopterus, is an open water, free-swimming freshwater aquarium fish from the small streams and rivers of Thailand, Borneo and Sumatra. It will grow to 14 inches in length, which is far too large for your 10-gallon aquarium.
The bala shark is an easy fish to maintain and grow if it has a large enough aquarium to swim freely in and the aquarium is kept covered (this species jumps when scared or stressed). It does well in a community aquarium of similarly sized fish. Feeding is not a problem. At small sizes it is an omnivore and will eat almost any normal aquarium fish food. The bala should have some vegetable matter in its diet. When the bala shark reaches maturity, about the time it reaches 9 inches in length, it begins to change its diet and will chase and eat small fish.
The term “shark,” when applied to freshwater aquarium fishes, almost always refers to ornamental fish of the family Cyprinidae (or minnow family) and implies that the species has a slightly enlarged dorsal fin that is held erect when the fish is swimming. Shark is a trade name intended to help sales.
Giving additional thought to your “cleaner fish,” I wonder if what you meant was “scavenger,” a misnomer that is frequently attached to catfish. If this is the case, then yes, you can keep catfish in with the bala. Remember, however, that you have to feed them just like the other tropical fish in the aquarium. They are not there to clean the aquarium — they are there because they are excellent aquarium fish in their own right.