> Question to other apistophiles: the sexing method I mention above > seems to work well for many spp. I'm familiar with, but I'd like to know > with which spp. this technique wouldn't be helpful. Quite a lot especially if you are looking at young fish or those in unsuitable conditions in a shop tank where their colour pales. A lot of young fish look very similar in terms of colouration. Regarding the black ventral fins most (all?) females show the black colour when spawning but not neccessarily at other times. Ken.