Mottled Bichir

About

The mottled bichir (Polypterus weeksii) is one of the rarer members of its genus to make it into the hobby, and that alone makes it worth knowing. Native to the middle Congo River basin across the Republic of Congo and the Democratic Republic of Congo, it belongs to a lineage with fossil relatives dating back over 200 million years. Long before many modern fish groups even existed. That ancient heritage shows in its biology: like other bichirs, it uses a divided swim bladder as an accessory breathing organ and must have access to surface air or it can actually drown. Young fish take this even further, retaining external, feathery gills far longer than other Polypterus species do. In the aquarium, this is a nocturnal bottom dweller that hunts almost entirely by scent, since its eyesight is genuinely poor. It is a committed carnivore and will eat anything that fits in its mouth, so tankmates need to be chosen with that in mind. Other bichirs, larger knife fish, sizable Synodontis catfish, and robust characins tend to work well. Beyond the predation risk, it is relatively peaceful and quite hardy, which puts it within reach of an intermediate keeper willing to provide the substantial space a fish of this size demands. Most individuals in the trade are wild-caught, so quarantine and careful observation after purchase are genuinely worthwhile habits here.