Delta / Super Delta
A variant of Betta (Betta splendens)

Photo: Dvortygirl · CC BY-SA 3.0
A betta with a triangular tail that widens toward the edge but does not reach the full half-circle of a Halfmoon.
A variant of Betta (Betta splendens)

Photo: Dvortygirl · CC BY-SA 3.0
A betta with a triangular tail that widens toward the edge but does not reach the full half-circle of a Halfmoon.