Halfmoon
A variant of Betta (Betta splendens)
A selectively-bred betta whose caudal fin spreads to a full 180-degree half-circle when flared.
Keeper tips for this variant
That huge sail-like fin is prone to tearing and fin-rot — keep snag-free décor (no plastic plants) and immaculate, warm water (78-80°F) to support fin regrowth.