What causes tropical fish to lose their buoyancy?

Question

All the fish in my community tank do fine floating effortlessly about. But every now and then one will struggle big time just to keep adrift. This usually happens a few weeks before they die. Is there anything I can do to help the poor guy when this occurs...and what causes this loss of buoyancy?

Answer 1

This could be caused by a number of things, from minor constipation, an infection, malfunctioning duct, or even internal bleeding.  Really, without specific information, I'd guess your water quality isn't where it should be.  High levels of ammonia can destroy organs (most notably the kidneys and liver), and this can lead to poor fluid regulation and loss of bouyant control.  If your ammonia and nitrite levels aren't at 0 ppm each, you've got a problem.

Answer 2

look it up on google