Yes I'm sure we will be putting him out of his misery shortly. I just wanted to doublecheck with some fellow fishkeepers about what he might have. Plus last night when we tried to catch him to do just that he was zipping all round the tank to get away, so I figured maybe he had some more life...
Thanks for everyone's replies. I hadn't heard of this dwarf gourami iridovirus disease but the symptoms (except for the lesions - none I can see on my fish) do sound very similar. Sounds like he's a goner then. I'm just surprised it's hanging on in there so long! Also, surprised it took so long...
I've got a gourami that's been steadily going downhill. It started becoming listless, and hanging around near the top of the tank gasping a few weeks ago. I assumed there was an oxygen issue but did a water test on all the usual factors and everything was fine, and in addition all the other fish...