A bichir is a freshwater fish belonging to the family Polypteridae. Though there are 12 separate species of bichir in existence, each is native to Africa and shares several unusual features with its relatives. Specifically, bichirs have a number of small dorsal fins, armor-like scales, and a primitive lung system which allows them to take breaths above water. While bichirs are carnivorous, they are not particularly aggressive, making them a somewhat popular choice among aquarium hobbyists.
The 12 existing species of bichir are found throughout the freshwater systems of Africa, and are generally nocturnal animals. Thus they tend to spend the bulk of the daytime near the beds of the lakes or rivers in which they live, hiding among plants and under rocks. They become active at nighttime, when they venture up from the depths to hunt for food. Bichirs have a keen sense of smell, and are known to swim into swamps and marshes in search of prey.
Due to its unusual appearance, the bichir has earned the nickname “dinosaur eel” among many fish enthusiasts. It has a tube-like body which can grow to over 3 feet (91.44 cm) in length. In addition, its back is lined with a single-file row of eight to 15 sharp-edged miniature dorsal fins, or “finlets.” It possesses short, wide pectoral fins which allow it to “walk” across the water bed. Also unusual are its extremely tough scales, which equip it with a kind of natural suit of armor.
Another distinguishing feature common to the 12 species of bichir is the possession of a primitive lung system. These lungs take the place of the buoyancy-regulating swim bladder found in most fish. They also allow the bichir to breathe by lifting their heads above the water’s surface. This unusual breathing system makes it possible for bichirs to continue accessing oxygen even when the water in which they are swimming is of poor quality.
Bichirs are carnivorous animals which feed on prey such as worms and small fish. When fed regularly, however, they tend to be fairly docile animals, and generally do not show aggression toward the fish which surround them. This docility combined with their unique appearance make them a somewhat popular choice among freshwater aquarium enthusiasts. Before adding a bichir to an existing tank, however, aquarists should be aware that the fish may be attacked by plecs or other algae-eating fish, which may be attracted to bacteria growing on the bichir’s scales.