Female sp Schwarzkehl, or other species??

[RustedKnight]

In my group of Apistogramma sp Schwarzkehl there is a single presumed female which the domainant male seems rather fond of.

My problem lies in the fact that "she" doesn't have the black strip underneath. Could you ID or Sex this fish for me as if it isn't sp Schwarzkehl I want to remove it before any possible crossbreeding occurs.

Here are 2 images of the fish in question.

second shot showing lack of black marking underneath;

 

[Mike Wise]

How big is this fish?

 

[RustedKnight]

She is somewhere in the region of 2.8-3cm

 

[Mike Wise]

Your fish probably is Schwarzkehl, but 'odd' about the chin stripe. It isn't unusual for fish to 'lose' a pattern, especially young/domestic fish. I really can't say if it is a male or female from the photos. The fish probably is still juvenile, but I would expect to see black pigment on the leading edge of the ventral fins on juvenile and/or female specimens.

 

[RustedKnight]

Definately a juvenile, and wild caught. I'll just have to keep an eye on her as she grows. Need to move all these fish anyway, damn cyanobacteria bloom in the tank, needs to be stripped.
Too much sunlight, :/

Thanks for the help and info Mike, appreciate it, as always.