I'm afraid the photo is nearly not as good as it should be for any kind of helpful diagnosis. They are obviously filled with something. Had the fish been in quarantine, I would anesthesize the fish and find out if it contains a liquid or a solid, then consider an operation.
Regarding spreading. . .as previously posted, it depends on what it is from. You need to implement a quarantine program if you are going to acquire fishes, especially if you don't have a chance to reject the fish before you get it. This is one of those fishes that would not get sold from an LFS to a smart hobbyist. Yet, quite often this is the quality of fishes I see shipped from wholesalers and importers to their retail buyers. Just to be clear. . .this isn't because they are knowingly sending out sick fishes, it's just that the help just doesn't look that closely at the livestock they ship.
If the above (anethesize, investigate, surgery) is something you are not going to do, then move the fish to a hospital tank and treat with a systemic antibiotic, such as Maracyn Two for saltwater fishes. Use a dose TWICE that recommended on the medication container/literature. If the problem is bacteria based, this will help.
