Something Wrong With Pleco

[y2klovebug]

My bristle nose Pleco is about 2 years old and in the last 2 days I have noticed he is out in his tank a lot my than normal (he is normally very shy and hides most of the time) he has developed these two lumps behind his fins, one each side but one considerably bigger than the other and also a couple on the top of his back behind his top fin (sorry I don't know the technical terms) his breathing also seems much more laboured than normal. Really concerned about him, so does anyone have any experience with this as to what it is and what we can do to help him? I have done a half a tank water change today to try and help. We had also bought some different food which we were phasing in but we have cut that out completely.

I have put some pictures below which will hopefully show what I mean better than I've managed to explain it!