Serpae Tetra (Hyphessobrycon eques)

Hyphessobrycon eques is one of the more visually striking tetras in the trade, deep red body, black-edged fins, but it's also got a real reputation as a fin-nipper, and that reputation is mostly a numbers problem: in a group too small, boredom and unspent aggression get directed at slower tankmates. Bump the school size up past six or eight and that same energy gets absorbed internally as normal shoal dynamics instead. Worth the extra numbers for how good a proper serpae school looks.

Care level: Easy · Temperament: Semi-aggressive, shoaling · Max size: ~1.75" · Min tank: 20 gal · Diet: Omnivore, flake/pellet