Wide halftooth characin

About

Found across several major South American river systems, including the Amazon, Negro, Madeira, and Essequibo basins, this active schooling fish, Hemiodus atranalis, is one of several similar-looking species in its genus that rarely turns up in the hobby. They all share a broadly comparable body plan and can be tricky to tell apart without a close look at the fin and body patterning, which varies subtly between species. In the aquarium, Hemiodus atranalis is peaceful by temperament, but its size and near-constant movement can unsettle smaller or more timid tankmates, so it pairs best with fish that can hold their own. Think similarly-sized characins, eartheater cichlids like Geophagus or Satanoperca, and robust catfish or loricariids. This is a shoaling species through and through, and keeping a good-sized group not only looks natural but actually helps the fish settle in. New arrivals tend to be quite skittish, sometimes for weeks, but they calm down noticeably once they feel secure in a spacious, well-planted tank. Breeding in captivity has not been documented, though egg-scattering seems the likely mode of reproduction given what's known about related species. Broadly suitable for beginner keepers who can meet the space requirements.