maybe your airline is defective has a hole or pinch.... try other airline and see. as many ppl said, it's leaking air somewhere and need to find out where it's leaking from. check and see all connectors make sure they are no air leaks from intake hose including bearings that spins and pinch...
I'm looking to get some cheap hang-on back type of skimmer for my QT setup. Do you have something that you dont use?
also, those hang on wheel type filtration would do too.
Best bet is.... take it out of your tank and QT the fish for several weeks either copper or Hypo method. If you can't catch it, if it still eats give him good amounts of food make him fat. If fish does not eat then it's bye bye~~
lol... I gave up!!! trying to get multi frags so I get worth a paying for $40.00 shipping fee but, can't win the bid!!! alot of last min bid snipers out there lol.