Heehee...see my post on Breeding Season. It sounds like your Mister Fish is...in the mood. As long as the spots are on his gills and fins, not his whole body, it might just be breeding tuburcles, as you said. It seems they get a little more aggressive when that special time comes around. And your girl, if she is a girl, may not be left out for long.
Keep an eye out for eggs- I know we are.