The halfmoon is a Betta splendens variety with a semi circular tail. These bettas may not appear to have this shaped tail at first but when it is held completely erect it should have a 180 degree angle. The actual length of the tail can vary but should be as rounded and even as possible to be considered a good quality betta halfmoon.

This is a fairly new betta splendens variety. The halfmoon betta has only really become widely available in the last decade. A visit to a well stocked store or online fish dealer will reveal a range of colors and patterns all available with the halfmoon tail.