As you window shop the fish in your aquarium shop, you may be struck by a few called “sharks.” While not in any way related to the type of predator made famous by the movie “Jaws,” they do have large fins and shark-like movements. They can also grow large, become aggressive in the tank – and even jump out.

While these are attractive, generally hardy fish, easy to care for and interesting to watch, only a couple of species make for good fish in the community aquarium. The smallest of them will grow to around 5 inches, the largest to nearly 2 feet. They are fast swimmers and need room to move. Most do not do well with others of their kind, either.

Types of Tank Sharks

The red-tailed black shark is the most shark-like of the group. It is impressively colored: velvet black with a bright red tail fin. It has a shark-like swimming motion and can become the center of attention in the tank. The problem is that it is an aggressive fish and should only be kept in tanks with fish its own size or larger. It grows to about 6 inches and is tolerant of pH variations, although it does best in slightly alkaline water.

The Apollo shark, a long narrow fish, dull silver with greenish highlights, is another “shark” to avoid in the community tank. It grows to about 10 inches and is highly aggressive toward its own kind.

The ruby shark, which grows to 6 inches, is a better choice for the community aquarium. Best of all is the bala shark, also called a silver shark or tri-colored shark. This long slender fish is silvery with colorless fins edged in black. It grows to 12 inches, readily eats flake food and appreciates tubifex worms. While mostly peaceful, it is a large fish that should be kept in at least a 20-gallon community tank.

Beware: These sharks are exceptional jumpers and have no problem launching themselves 2 feet above the tank. Make certain that the tank cover actually covers the entire tank, and use caution when making water changes or you may find your shark on the floor.

Black sharks are also peaceful fish – as well as being good algae eaters – but at a length of 22 inches, they need plenty of room.