Thanks Neil, I'm pretty sure its a female but luckily my brother has the only other one left from the group which is smaller but im pretty sure is a male
From your photos etc it looks like it has some red underneath the head around the throat and gills. I noticed when I had these previously the males didn't.
I recently obtained 6 more young Chancho's and the 2 largest are about 3", one has the tell tale red around the throat area and the tail and unpaired fins seem redder. The other is a more yellowish colouration all over, no red around the lower throat.
Your right, the other one my brother has doesn't have the red. I also noticed the black blotch on mine on the dorsal. Funny thing is that out of the 6 she was the biggest and most dominant of the group.