Freshwater Butterflyfish

The freshwater butterflyfish is a relatively small species, usually reaching no more than 13 cm (5.1 in) in length. Its pectoral fins are very large relative to body size. It has a large and well-vascularized swim bladder, enabling it to breathe air at the surface of the water. It is carnivorous, feeding primarily on aquatic insects and smaller fishes. The freshwater butterflyfish is a specialized surface hunter. Its eyes are constantly trained to the surface and its upturned mouth is specifically adapted to capturing small prey along the water surface. If enough speed is built up in the water, a butterflyfish can jump and glide a small distance above the surface to avoid predation. As it glides, it wiggles its pectoral fins with the help of specialized, enlarged pectoral muscles, and it is this ability that gave this fish its common name. When freshwater butterflyfish spawn, they produce a mass of large floating eggs at the surface. Fertilisation is believed to be internal. Eggs hatch in about seven days.

The freshwater butterflyfish is commonly seen in Lake Chad, the Congo Basin, throughout lower Niger, Cameroon, Ogooue, and upper Zambezi. They have also been seen in the Niger Delta, lower Ogooue, and in the lower Cross River. Within these bodies of water, this species is found in slightly acidic standing water with high amounts of surface foliage for cover. This species requires a year-round temperature of 73–86 °F (23–30 °C).