First off... I have the WORST luck with buying young fish and thinking they are male, and then turn out to be female.
Last night, I had a couple surprises...
The OB Peacock that I moved into my big tank because it was too aggressive in my peacock tank... its holding. I would have bet money that it was a male.
And my Venustus, which I was sure was a female... but I liked the color, so I didnt mind... now has a blue face!!! Cool.