Royal Dwarf Gourami Dying. Help!

I have 2 royal dwarf gourami, had them both about 8 months along with other fish, tank cleaned regularly and all fish great up until a few weeks ago, my two gourami became extremley bloated and very lethargic, i was informed this could be biopsy and got some anti bacterial fish treatment, one fish still bloated and moves about a little the other gone dead thin and has developed a weird absecc/cotton wool spot on rear of body and just lies at bottom of tank breathing.

 
I have been treating using Anti white spot and Anti bacteria (Interpet treatments)

Well, since they don't have white spot that shouldn't have been used. I doubt it's bacterial either. And biopsy is a surgical procedure, not a disease.
 
They likely have what's called dwarf gourami disease. The fish you've pictured should really be euthanized as it's suffering and won't recover. 
 
I may be wrong about the ailment (but I don't think so) but not wrong about putting this fish out of its misery. 
 
If anything other than DGD, I would guess some kind of internal parasite. 
 
Chime in, more experienced fishkeepers!

My 4 dwarf gourami's went the same way, after much research I diagnosed DGIV - it is incurable and the fish only stand to suffer.  It would be my advise to euthanize.

extremley bloated and very lethargic, i was informed this could be biopsy...................i think he might mean dropsy

I hope the poor thing has gone to fishy heaven by now.