Crowntail Male Betta (Betta splendens)

The crowntail's spiky fin rays aren't decorative filler, they're a genetic mutation that lets webbing recede between the rays, first fixed as a stable line in Indonesia in the 1990s and now one of the most recognizable fin types in the hobby. The effect only gets more dramatic on a full flare, when those individual rays fan out like a crown. Solo housing only, males don't share water peacefully.

Care level: Easy · Temperament: Aggressive toward other bettas · Max size: ~3" · Min tank: 5 gal · Diet: Carnivore, betta pellets + frozen