Senegal bichir

Water parameters

Tolerated range for this species. Aim for the middle of each band rather than the extremes.

Tank and habitat

Substrate: sand.

Behavior

Plant interaction: may nibble soft.

Feeding

Sinking carnivore pellets, frozen bloodworms, prawns, silversides, earthworms. Poor eyesight; hunts by smell. Feed at lights-out for best feeding response. Will eat any fish small enough to swallow.

Nocturnal feeder; drop food after lights out.

Compatibility

• Living fossil. Polypteridae have existed for 100+ million years; the dorsal finlets, ganoid scales, and lobed pectoral fins are all primitive features
• Obligate air breather. Must have access to the surface; they drown in nets or traps that prevent surfacing. The lung is a modified swim bladder
• Escape artist. Will find any gap in the tank lid and push through it. Bichirs can survive out of water for hours breathing air, so you may find one on the floor still alive
• The 'dinosaur eel' common name is doubly wrong (not a dinosaur, not an eel) but it sells fish to people who want something unusual
• Compatible with similar-sized non-aggressive fish: large peaceful cichlids, larger catfish. Will eat anything it can fit in its mouth, which is wider than it looks

Origin and habitat

The most widespread species in the genus Polypterus, distributed across tropical Africa from the Senegal and Gambia rivers through the Niger, Volta, and Chad basins to the Nile River basin, Lake Turkana, and Lake Albert; a subspecies (P. s. meridionalis) occurs in the middle and upper Congo basin. Described by Cuvier in 1829. Inhabits marginal swamps, freshwater lagoons, lake margins, and the muddy edges of rivers; prefers shallow, slow-moving water with vegetation. Has a modified swim bladder that functions as a primitive lung, allowing atmospheric air breathing and survival in oxygen-depleted environments; can survive out of water indefinitely provided the skin stays moist, and can use its pectoral fins to move on land. Usually grey or beige with occasional darker blotches; albino individuals also occur in the trade. The recorded maximum is 70 cm standard length, though aquarium specimens are typically much smaller. Poor eyesight; relies heavily on sense of smell to detect prey. The most commonly kept bichir species in the aquarium hobby due to its relative availability and somewhat smaller typical captive size compared to larger congeners. One of the most peaceful and active Polypterus species; recommended as a beginner's bichir. Very long-lived; specimens exceeding 34 years have been reported in captivity. IUCN Least Concern.

Breeding

Rarely bred in home aquariums. Males have a wider, thicker anal fin than females. Breeding requires a large tank (400 L), heavy feeding with live food, and a water temperature around 28–30°C. Males cup the female's anal fin during spawning and eggs are scattered among plants. Eggs hatch in 3-4 days. Fry have external gills (like axolotls) for the first few weeks.

Common problems

Predator that eats anything it can swallow, which includes surprisingly large prey for a fish that looks slow. Small tetras, shrimp, and anything under 5–6 cm is food. They're also escape artists with a primitive lung that lets them survive out of water for extended periods. A weighted lid is required. Poor eyesight means they find food by smell, which makes feeding slow; ensure tankmates don't eat everything before the bichir finds it.

Bioload

Further reading

• How to cycle a fish tank
• Stocking ideas by tank size