Aquarist Atlas
Aquarist Atlas · the bichirs & ropefish

Bichirs & Ropefish

The bichirs and the reedfish — the family Polypteridae — are the most ancient living ray-finned fishes, a lineage that has kept its lobed, limb-like pectoral fins, its saw-tooth row of dorsal finlets and its heavy armour of interlocking ganoid scales almost unchanged for a hundred million years. They are the only aquarium fish that breathe air with true lungs, rising to gulp at the surface and able to survive out of water in damp conditions. All are African — cylindrical, nocturnal, scent-hunting predators of the Nile, the Congo, the Niger and the West African swamps, from the foot-long Senegal bichir to the metre-long giant Congo bichir and the slender, snake-bodied ropefish. This section is built to the same standard as the cichlid, cory and pleco pages: researched, cited accounts with no Wikipedia and no invented facts.

© Adobe Stock

Bichirs are living fossils that breathe air. Behind the gills sits a pair of primitive lungs, and a bichir that cannot reach the surface to gulp can actually drown — so a tank needs an air gap above the water and a fish that is never sealed under. Two things define keeping them. First, a tight, gap-free lid: these are determined escape artists — the ropefish above all — and a bichir on the floor is the single most common keeper tragedy. Second, respect the predator: they hunt by smell in the dark and will swallow any tankmate small enough to fit, though they are otherwise peaceful with fish of similar size. Their ganoid armour makes them hardy — the opposite of the medication-sensitive scaleless catfishes — but most are wild-caught, and only a few (the Senegal bichir chief among them) are farm-bred. Watch the adult size: most reach 30–40 cm, but the giant Congo bichir approaches a metre. They are rarely bredin aquaria — external fertilisation, eggs scattered on plants, no parental care.

An ornate bichir patterned with a bold yellow-and-black reticulated network across its body, dorsal finlets and pectoral fins, over pale gravel
The ornate bichir (Polypterus ornatipinnis) is the showpiece of the family — a large Congo-basin species marbled in a bold yellow-and-black net across its body, its row of dorsal finlets, and even its pectoral fins. Behind the spectacle is the same ancient design every bichir shares: interlocking, enamel-hard ganoid scales, lobed limb-like pectoral fins, and a pair of primitive lungs it fills by gulping air at the surface.
A reedfish, a long, slender, snake-like fish, coiled on aquarium gravel in front of driftwood
The reedfish or ropefish (Erpetoichthys calabaricus) is the eel-like outlier of the family — long, slender and lacking pelvic fins. It is a legendary escape artist that will find any gap in the lid, so a tight, fully-covered tank is not optional but essential.
An albino bichir, its body pale cream and its eye pink, gliding past aquarium plants in dark water
Albino and “platinum” bichirs — pale, pink-eyed colour forms bred for the aquarium — are among the commonest bichirs in the trade. Bichirs are nocturnal, scent-hunting predators with poor eyesight: peaceful with fish too big to swallow, but a real threat to any tankmate that fits in the mouth.

Photos © Adobe Stock

14 species in the atlas

We cover the whole family Polypteridae — the African bichirs and the reedfish — grouped into the bichirs (genus Polypterus) and the eel-like ropefish (Erpetoichthys calabaricus). Sizes are given as total length. Following the Catalog of Fishes, the valid set is written up as each species is researched; long-synonymised names such as lapradei, katangae, buettikoferi and lowei are folded into their current species rather than listed separately.

Species

14 of 14 species

Bichirs · 13

The bichirs — genus Polypterus — are the cylindrical, armoured predators of African fresh waters, from the foot-long Senegal or 'dinosaur' bichir (P. senegalus) to the metre-class giant Congo bichir (P. congicus). All share the family's lobed, limb-like pectoral fins, a saw-tooth row of dorsal finlets, heavy interlocking ganoid-scale armour, and a pair of primitive lungs for gulping air at the surface. Nocturnal, scent-hunting bottom-dwellers that will swallow any tankmate small enough to fit.

Ropefish · 1

The reedfish or ropefish — Erpetoichthys calabaricus, the single species of its genus — is the eel-like outlier: a long, slender, snake-bodied bichir of West and Central African coastal swamps that has lost its pelvic fins entirely. It breathes air, hunts by scent at night, and is a notorious escape artist that will slip through the smallest gap in a lid.