The flame red dwarf gourami is a male too. The female flame dwarf gourami is silver grey all over. See following link. If it has any red its a male.
http://www.premierpet.com.au/GOU201_dash_04/FEMALE-DWARF-GOURAMI/pd.php
The fat belly could be a tumor, too much food or an internal bacterial infection.
Unfortunately all the colour forms of the dwarf gourami (Trichogaster lalius) are riddled with diseases and the two most common ones found in these fish are the Iridovivus and Tuberculosis (TB). Neither can be cured and both usually kill the fish within 6-12 months of people buying them. Personally I tell people to avoid dwarf gouramis and all their colour varieties because of these diseases.
There's a bit more info on them at the following link.
https://en.wikipedia.org/wiki/Dwarf_gourami