African Arowana

The African Arowana (Heterotis niloticus), also called the bonytongue, is a large freshwater fish in the family Osteoglossidae, native to rivers, lakes, and floodplains across tropical West and Central Africa. Unlike other arowanas, which are predatory surface hunters, this species has evolved specialized gill-arch structures for filter feeding on plankton and organic detritus. It is a widespread and adaptable species across its native range, capable of building bubble nests and tolerating strongly seasonal floodplain habitats typical of tropical Africa.

African Arowana can be identified by these features:

• Elongated, moderately deep-bodied form covered in large cycloid scales
• Dark grey-green to bronze coloring, generally uniform without bold markings
• Small, downturned, toothless mouth adapted for filter feeding rather than grasping prey
• Long, low-based dorsal fin running along much of the back
• Rounded tail fin

Its toothless, filter-feeding mouth is the key trait separating it from predatory arowanas such as the Jardini or Silver Arowana, which have large upturned jaws built for snapping prey.

This species inhabits freshwater rivers, lakes, and seasonally flooded plains across West and Central Africa, including the Niger, Chad, and Nile river systems. It favors shallow, vegetated floodplain waters where suspended plankton and organic material are abundant, and tolerates the strong wet and dry season cycles typical of African floodplain habitats. African Arowana can also use an air-breathing organ to survive in warm, oxygen-poor water common in stagnant floodplain pools during the dry season.

African Arowana feed by filtering plankton and fine organic detritus from the water using specialized gill-arch structures, a feeding strategy distinct from the predatory habits of other arowana species. They can breathe air using a modified swim bladder, allowing survival in warm, low-oxygen floodplain waters. During the breeding season, adults construct large, dome-shaped bubble nests from aquatic vegetation at the water's surface, where eggs are laid and guarded by a parent until the young disperse. This nesting behavior and filter-feeding strategy make the species ecologically distinct within the arowana family.