While the following description and possible treatment options are vague, this is a constellation of diseases that can lead to these signs in a sick fish. These signs are usually indicative of a GI or swim bladder problem in marine ornamental fish (especially if floating) however a systemic infection is also possible. Usually it is difficult to diagnose the disease unless the cause can be deduced from recent events (i.e. massive water change/poor water quality, power outtage, change in diet, feeding from surface and bubble swallowing, disease outbreak with other fish). These events may directly cause gas/fluid to be in places they don't belong or can be stressors which may an internal malfunction/opportunistic infection leading to gas/fluid in places they don't belong.
The treatment of this is again not guaranteed but a flake food medicated with kanamycin is often your best bet. If you can catch the fish a kanamycin ( kanacyn by seachem) dip at 50mg/l for an hour in a bucket of an appropriate amount of water may work if it truly is a GI issue. If it is internal, catching the fish and doing a 7-10 erythromycin (maraycn) treatment in a quarantine tank is a "no other option" option. There is a prescription drug which a veterinarian may use if a fish has gas build-up in the stomach (or pouch of a seahorse for example) or behind the eye called a carbonic anhydrase inhibitor. Acytlezolamide and dorzolamide are used for diseases which produce carbon dioxide gas in body cavities and can prevent both the organism and/or associated bacteria from making gas in the wrong place in the body, thus allowing for the body to heal and hopefully not bloat any more.