I just got a pair of apisto triple reds. One is certainly male, but the other I can’t tell. They were sold together but with uncertainty about the smaller/lighter one’s sex. They certainly look different and it has some yellow that has gotten brighter as it has settled into the tank but the pelvic fins are not black. Interestingly, the smaller one seems more confident in exploring the tank. First picture is the obvious male. Others pictures are the one in question.