koi

  • We are currently upgrading MFK. thanks! -neo
It is not easy when the fish are small but one mature (12" or so) females have fuller body shapes and rounder fins while males have more pointed fins, the pectoral fins are often opaque, and have a raspy texture to their gill plates.
 
is this the same with goldfish with the round/pointed fins and body size part?
 
Goldfish have less difference in the finage and many of the fancies are hard to sex but when ready for breeding the males get tubercule on their gill covers.
 
MonsterFishKeepers.com