bichir

Bichirs are a family of primitive ray-finned fish belonging to the order Polypteriformes. They are native to freshwater habitats in Africa, with one species also found in the Congo River basin. Bichirs are characterized by their elongated bodies, dorsal fins that are segmented into several smaller finlets, and large, ganoid scales that are thick and bony. They possess lungs in addition to gills, allowing them to breathe atmospheric air, and often spend time near the surface of the water.

These fish are typically solitary and predatory, feeding on small fish, crustaceans, and insects. They are often referred to as "living fossils" due to their ancient lineage and many of the same physical characteristics as their fossilized ancestors. Bichirs are a popular choice for aquarium enthusiasts due to their unique appearance and interesting behaviors. Several species are kept in captivity, with the Senegal bichir and the delhezi bichir being among the most common.

The family Polypteridae contains two genera: Polypterus and Erpetoichthys. The Polypterus genus includes the majority of bichir species, while Erpetoichthys contains only the reedfish or ropefish, which has a more snake-like appearance and lacks the characteristic paired pectoral fins of other bichirs. Despite their ancient lineage, bichirs are a successful and enduring group of fishes, adapted to a variety of freshwater environments.