I work at a fish store and we recently purchased fish from a wholesaler about 3 days ago. On one of the filefish i noticed a large lump on his side. The lump is soft to the touch. Feels like an air bubble. He was swimming around fine and eating for first 2 days. Now things aren't looking to hot. I dont know how much longer he will make it. I'm debating trying to cut him open and release it if it doesnt get better in the next couple of days. Any opinions?