Koi Betta
Betta splendens
About this strain
Koi Bettas display patches of red, orange, black, and white arranged in irregular blotches reminiscent of Nishikigoi (ornamental koi carp). The patterning is bold and high-contrast — no subtle gradients, just chunky color fields that shift across the body and fins. Because Koi Bettas typically carry the marble gene, their coloration can change dramatically over their lifetime, which is either exciting or frustrating depending on your perspective. No two fish are identical, and a fish that looks mediocre at purchase may develop stunning pattern over 6–12 months — or vice versa. Buy a fish whose current pattern you love, and treat any future changes as a bonus.
Origin
Koi Bettas were developed primarily by Thai breeders in the 2010s by selecting marble-gene bettas for koi-like patterning. The variety exploded in popularity worldwide after roughly 2015 and is now one of the most commonly bred fancy color strains.