What does "heavy breathing" mean?

[mangelo]

I know that there is a term for it, but my blue spot jawfish appears to be breathing very heavily and not moving. I know that it probably means he's dying. I am so distraught about it and don't know if there is anything that I can do.

Why do fish do this heavy breathing before they die?

Is there ANYTHING that I can do?

[MrTuskfish]

Heavy breathing is a symptom, so there must be an underlying disease/condition. This isn't necessarily fatal, but we need a lot more info to be of help. General appearance, appetite, fish's history, wounds or spots, water parameters, tank size, anything harassing him,.....whatever you can tell us. Still no guarantee, but there's nothing to go on, a pic would help too. Oh yeah, any skin problems, like excess slime coat, skin seems to slough off? A stab in tyhe dark, but jawfish are prone to brooklynella-type diseases, nasty stuff.