Ray-finned Fish, Anostomidae

Anostomidae is a family that holds over 140 species of ray-finned fish that reside in freshwater habitats from northern South America to Central Argentina. The scientific name of this family means mouth on top and it is thought to be most closely related to the toothless characins, the Chilodontidae headstanders, and the flannel-mouthed characins. Although this family is currently monotypic, some experts suggest that there is enough evidence to classify some of the genera within it, including the Rhytiodus genus and Schizodon genus, as sub-families.

Members of the Anostomidae family, collectively known as Anostomids, have long bodies that reach an average length between 5.9 and 23.6 inches. Their heads are elongated and taper to straight noses and small, upturned mouths. Many species of headstanders, which swim with their mouths facing upwards or downwards, are classified within this family, including the marbled headstander. The jaws of Anostomids are short and contain two rows of six to eight teeth, which are used to feed on detritus and invertebrates along the beds of lakes and rivers. Some Anostomids are considered edible, particularly the larger species.

Image Caption: Abramites hypselonotus. Credit: Haplochromis/Wikipedia (CC BY-SA 3.0)