Growing to be almost three feet long, the clown knifefish (Chitala chitala) is found in the rivers and wetlands of southern Asia. This fish swims equally well forward or backward, with an undulating motion of its large anal fin. It is often seen at the surface, splashing as it rolls over, exposing its silvery flanks. It’s also popular as an aquarium trade fish.
It is also a member of the order Osteoglossiformes, which are bony-tongued fishes. This order of fish also includes the arapiama, the freshwater butterflyfish, and the elephantnose fish. Bony-tongued fishes are named after the tooth-studded tongue and palate found in most species. Most fish of this order are relatively large (up to 3m long) and live mainly in freshwater in the tropics.