I'd look up Dropsy if I was you, just to be on the safe side. The "all over bloating" you described sounds like it could be Dropsy. Do the fishes scales stand out? Making him look like a pinecone? If so, then it is likely Dropsy.
I don't think it is a bubble nest building behavior unless there are a lot of bubbles as the end result, bubbles that don't pop easily.