question on pectoral fin colouring

[anewbie]

For some reason i thought females had black on the pectorcal fins and male clear; or at least this is the case of most species of apisto i've kept; however this is a wc cockatoo and well he clearly didn't get the message or just as likely i'm clueless about the sex:

 

[MacZ]

This is definitely a male. The way the fins have grown out is obvious.

The "black-in-the-pectorals" thing is not a general thing that applies to all species and breeds. It helps with the usual suspects you get in every backwater petstore and if you have juveniles to sex, but come on, this fish is fully grown and the colours and fins say everything.

 

[Frank Hättich]

The males of most (probably all) Apisto species can show more or less pronounced black anterior edges in their ventral fins (not pectoral!). It's just that females do so more regularly and in a more pronounced way.
E.g. this is a proven male A. flavipedunculata: