It does sound like swim bladder, Hope this helps,
Swim-bladder Disease
Tropical fishes are often kept at low tempertures in transit, and afterwards swim-bladder sometimes occurs. This is recognizable by the bahavior of the fishes. Specimens that are afflicted have difficulty in maintaining there equilibrium and sometimes fall " head over heals", making tumbling movements. Finally they rest at the bottom or, in other cases, they float at they surface.
In such cases the disease is obviously due to chilling, which may cause inflamation of the bladder wall. This is why swim bladder disease doesn't only occur when a fish is shipped in sold water but also in the cooler months if temps get too cold.
Other causes of swim bladder trouble are preasure from some internal organ, such may result from constipation or other affictions in which the volume of the internal organs increases. Alternatively, it may be due to a fatty degeneration of the tissues of the swim bladde itself.
Swim bladder disease is NOT fatal and under good conditions a fishes suffering from swim bladder can recoup and live normal happy lives.
Swim- bladder troubles are best prevented by giving fish a varied diet with sufficient supplies of fresh foods ( depending on the species ). Sudden changes of tempertures must be avoided, as should subjecting a fish to too low tempertures for long periods of time. Sudden chages in foods can also cause or bring on swim-bladder problems.
Removing ill fish and cutting back on the food , keeping temp at a moderate temperture and good tank conditions are IMO / IME the best cure. At times I have let the fish go 5 days without eating till he unswells. Yes, they will be hungry but they can regain the fishie fat. Nothing alittle food ( varied ) can't help.
Good Luck,
Danny
