I've asked the same question here already although I've been keeping them for many years. Years ago I was told the males have more pointed unpair fins and grow fin extensions while the females don't. I noticed the same on my female though, think depending on breeding stock, that isn't a reliable criterium anymore. Generally males end up bigger and show more colour in most cases. Then again, a dominant fish might appear more colourful than a subordinate etc. ... the two I have would display dark colours with lots of red to pale colours with a slight orange, depending on the circumstances, i.e. tank mates/hierarchy, mood, substrate, whatever. So don't ask me I believe to have two males but not 100% sure. They don't get along at all, but the pair I had would neither get along most of the time.

I was told the males top fin was much longer than the females (or the other way round-cant remember) and that the males are larger and more colourful