Molly Question Update, Can Anyone Shed Any Light?

[CruX]

We bought 2 white mollies about 9 months ago and kept them in a 2 foot tank. Recently we upgraded from our 2 small tanks and bought a 350L Juwel. I thought both mollies were males and we bought 2 sailfin molies. Recently one of the Mollies has nearly doubled in size and has become very fat. The fish shows signs (from what I have read on this site) that it is a male. I will try and post a pic if I can but while attempting to get him/her out of his/her shell does anyone know if it could be something else?

 

[dwarfgourami]

We'll wait for the pic. Could he be constipated? Try feeding peas, and see if that shifts it. Does he appear otherwise well?

 

[CruX]

He appears really very well. I will upload the pics later, struggled to get some good ones as when I get near the little tyke he shoots off. He used to play with his similar sized molly friend but now spends his time shoving his nether regions into the face of one of the sailfin mollys.

 

[CruX]

OK sorry for the delay, my camera lead is damaged and I only just sussed a work round. The pics aren't very clear and I have been trying to tempt him with peas.

This is him at play with some other live bearers, doesn't show his fat tummy off very well but I thought it was worth including.