Long-Fin Black Tetra (Gymnocorymbus ternetzi)

Same age-related fade from bold juvenile bars to soft adult gray as a standard black tetra, just trailing extended fins bred onto the caudal and dorsal that catch current in a way the wild-type body never had to deal with. The extra drag makes them a slightly slower swimmer, so give them tankmates that won't outcompete them at feeding time. Otherwise as hardy and easygoing as the classic form.

Care level: Easy · Temperament: Peaceful, shoaling (mild fin-nipper) · Max size: ~2.5" · Min tank: 20 gal · Diet: Omnivore, flake/pellet