Koi Betta (Betta splendens) (Tricolor Roundtail)

Koi bettas get their patchy orange-white-black pattern from the same marbling gene responsible for koi carp and calico goldfish, a transposon that jumps around the genome and keeps reshuffling pigment cells even after the fish is fully grown. That means the exact pattern on this fish today isn't guaranteed to be the pattern it wears in six months, which is half the appeal for people who collect them. Classic rounded tail, no crown or halfmoon spread here.

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