Senegal Bichir

The Senegal Bichir is a freshwater fish belonging to the family Polypteridae, an ancient group of ray-finned fishes that retains several primitive anatomical features, including paired lungs used for air breathing alongside gills. Native to freshwater habitats across West and Central Africa, it is one of the most widely distributed species in its genus. Its body is covered in thick, bony ganoid scales, and instead of a single dorsal fin it has a row of small separate spiny finlets running along its back, a distinctive trait shared by all bichirs. The genus Polypterus is considered an important group for studying the early evolution of ray-finned fishes.

Identify a Senegal Bichir by these characteristics:

• Dorsal finlets: a row of small, separate spiny finlets running along the back rather than one continuous dorsal fin
• Scales: thick, hard, diamond-shaped ganoid scales forming natural armor
• Body: elongated and cylindrical, somewhat eel-like
• Color: greyish-olive to tan, sometimes with faint darker mottling
• Fins: rounded, muscular pectoral fins used for slow, deliberate movement along the bottom

The segmented row of dorsal finlets is the single most reliable feature separating bichirs from true eels and other elongated freshwater fish.

Senegal Bichirs inhabit slow-moving rivers, floodplains, and seasonally flooded wetlands across a broad swath of West and Central Africa, including the Senegal, Niger, and Nile River basins. They favor warm, shallow, often turbid or vegetated water with soft substrates where they can move along the bottom using their muscular pectoral fins. Their paired lungs allow them to tolerate the low-oxygen conditions common in stagnant floodplain pools and swamps during the dry season. Water temperatures in their native range typically stay between 24 and 28 degrees Celsius, and they are generally found in still or gently flowing habitats rather than fast currents.

Senegal Bichirs are primarily nocturnal, bottom-dwelling predators that move slowly and deliberately along the substrate, using their pectoral fins almost like limbs to navigate through vegetation and debris. They regularly rise to the surface to gulp air using their paired lungs, particularly in warm, oxygen-depleted water. They rely more on smell and touch than vision to locate prey such as small fish, crustaceans, and invertebrates, especially in murky or nighttime conditions. Senegal Bichirs are generally solitary and can be territorial with conspecifics, and their retained primitive traits make them a frequently studied species for understanding vertebrate limb and lung evolution.