Ilasca

Ilásca is a genus of small, spiny, freshwater ray-finned fish belonging to the family Gymnotidae. These fish are native to the Amazon Basin and other river systems in South America. They are known for their elongated bodies, which are typical of knifefish, and their lack of dorsal and pelvic fins. The anal fin is long and undulates to provide propulsion.

Members of the genus Ilásca are generally nocturnal and possess an electric organ that generates weak electric fields. This electric field is used for electrolocation, allowing them to navigate and detect prey in murky waters where vision is limited. They feed primarily on small invertebrates and insect larvae.

The genus Ilásca was first described by ichthyologist Samuel L. McDade in 1974. The type species is Ilásca schindleri. Currently, there are a few recognized species within this genus, though research is ongoing and new species may be discovered.

These fish are relatively small, typically reaching lengths of only a few centimeters. Their coloration is usually dark or mottled, providing camouflage against the substrate of their aquatic environment. Due to their specialized habitat and habits, Ilásca species are not commonly encountered by casual observers and are of particular interest to ichthyologists studying neotropical freshwater fauna.