Synodontis nigriventris, the blotched upside-down catfish, is a species of upside-down catfish native to the Congo Basin of Cameroon, the Democratic Republic of the Congo and the Republic of the Congo.
Appearance and anatomy
Blotched upside-down catfish are small, reaching a maximum of SL. These fish have lighter colors on the top of their bodies and darker colors below used for camouflage. The lighter colors on the top of them make it harder for predators to see the fish when looking up toward the sky but only when the fish are swimming upside-down. Adults swim and rest upside down in the water. They swim faster when upside down, and are more likely to be upside down around objects or at the water bottom. The more objects around the fish, the more they tend to swim upside down. When close to an object, the fish puts its ventral side closest to the object. By swimming upside down when it feeds, it can readily catch prey at the surface from beneath.