Help please, Gourami has large bulge on side and cannot swim straight, really not looking well, other Gourami absolutely fine, tried to upload photo but can't.
Male or female? Gouramis can get tumours. If it is, there is nothing you can do to fix it. If female, it may be egg bound. Also not a lot you can do for that except gently try to press and see if you can expel anything. Whatever it is will be pressing on the swim bladder causing the swimming difficulties. I suspect there will be nothing you can do to help and if the fish looks to be suffering, put it out of its misery.
I have now had to euthanise it as the other fish were nipping him while he lay flat on the bottom of the tank, I do think a tumour as only on one side, not a good day