Win wrote:
i know these guys will prolly hate me for this suggestion... but if worse comes to worse... have you heard of venting? its common practice with sport fishermen.
www.flseagrant.org/program_areas/fisheries/venting/
I doubt whether this is the problem. Like the article states, when fish are brought quickly to the surface from quite deep water, the swim bladder often expands, often sticking out of their mouth. Making a small incision to release the gas often cures the problem. However, unless you know what you're doing, I wouldn't suggest that you start thinking objects into your fish.
Occasionally fish do develop problems with their swim bladder and normally there is nothing you can do about it. Apart from the fish not being able to hold its buoyancy properly, are there any other visible signs that look out of place?