The Argentine part is home to a total of 29 freshwater fish species, 18 of which are native.[36] The introduced are several species of trout, common carp, and various species that originated in more northerly parts of South America. The natives are osmeriforms (Aplochiton and Galaxias), temperate perches (Percichthys), catfish (Diplomystes, Hatcheria and Trichomycterus), Neotropical silversides (Odontesthes) and characiforms (Astyanax, Cheirodon, Gymnocharacinus, and Oligosarcus).[36] Other Patagonian freshwater fauna include the highly unusual aeglid crustacean.[37]