Platy with swollen body and clamped fins

Hi Everyone, I'm in desperate need of advice please. For some days my sole male platy has been suffering with a bent body, very swollen towards his tail to such an extent that the scales are raised like he has dropsy, his fins are clamped and he has whitish patches on his body. I've searched in loads of books for a disease causing these symptoms but cannot find anything. He is eating well.
Water parameters are all ok at
Ammonia 0, Nitrite 0, Nitrate 25 and Ph 7.6
I have attached photos but unfortunately they are not very good.
Any ideas what this could be?

Generally if you are still having problems with the same fish, and you have posted within the last couple of weeks, we prefer it if you can continue with the original thread rather than starting a new one. The other thread about this fish has background information that we would normally go through. Fortunately I was able to find the other thread quite easily.

I am still of the opinion the fish has a protozoan infection and possibly a bacterial infection. I suggested salt in the last thread but if that hasn't worked, then get a broad spectrum medication that treats fungus, bacteria and protozoan infections.

Most broad spectrum medications usually have Methylene Blue, Malachite Green and Formaldehyde. Sometimes they have other ingredients.