Because the swim bladder is an outpocketing of the gastrointestinal tract in many fish, poor nutrition is suspected as cause of some swim bladder infections.
And consumption of too much dry food is also "suspected" to be an irritant in fish prone to this condition, so it is often suggested that feeding thawed peas will help. Whether this is confirmed to effective is another matter.
It seems swim bladder problems can be especially prevalent in line bred short bodied/"bloat" shaped fish such as goldfish, blood parrots, and recently, other short bodied cichlids because the mutation that causes the form does not allow enough space in the body for a swim bladder to develop normally.
Excess air has sometimes been removed with syringe allowing the fish to right itself, but in over 50% of the cases it has been tried (that I've heard about), the fish died anyway.
