Sexing Paradise Fish

I am a little confused.
I recently bought two paradise fish, each about 3 or 4cm long, that I thought were a female and a male. The female was duller in colour, had less prominant fins, had a more rounded belly and was submissive to aggression from the male. In the last month however s/he has become just as colourful as the male (which is definitely male) and it's dorsal fin has become more pointed. S/he is also occasionally aggressive towards other fish.
Is she indeed a she or have I bought a male by mistake?
I have included a pic

Hello and Welcome, PJJ 

Perhaps you could pop over to the New Members' Area here and introduce yourself and your piscine pals. The more photos the better as far as we're concerned - of the fish, that is, not you!

Quote from: ColinB on March 10, 2014, 08:30:48 PM

your piscine pals.

How very rude

No, no, no..... silly girl!!! Not piscine à la Francais, piscine in Latin. Sheesh.  (I think I'm the first to use this smiley).

It is very hard to be sure. It is brightly coloured and has pointy fine = male. It does not have tail fin extensions and it is plump (if not fat) = female.

However, in the second photo the tail fin looks a bit ragged at the edge, and it does look a bit fat. I'm wondering if it is in fact a male, but one that is not in the best of health.
If you look down on this fish from on top, do the scales on the 'fat' area lie flat against its body or do they stick out a bit like a pine cone?

It may be just the photo, some of mine make the fish look very peculiar, but the paradise fish does look an odd shape. It appears to be bulging in just the front of its body, which doesn't look natural. You can see the actual fish - is it very bulgy under the gill area?

I'm a bit concerned that it might well be a male that has health problems - the ragged end to the tail fin, the bulgy area under the gills

If it eating, that is a good sign. Sick fish often go off their food.

I can only suggest keeping a close eye on the fish for now. They seem to be similar to siamese fighting fish (both anabatids, males don't get on, can be aggressive to other fish in the tank etc) and sff females can often be as aggressive as males. It is possible that you do have a female, just one at the more aggressive end of the spectrum.