What's Wrong With My Dwarf Cockatoo?

[Spank]

My favourite fish in my tank seems to have taken a turn for the worse. He's a large male cockatoo dwarf who has until recently been thriving.
Now though, it looks as if he's dislocated his jaw as he can't ever seem to close his mouth. This makes it impossible for him to eat, he tries but just ends up ramming the food that I try to feed him. So now he's found a corner of the tank and looks very down and dejected. I've had this guy for a while now and would hate to loose him so any ideas on what could possibly be wrong with him and what I could do about it would be greatly appreciated.

He's housed in a 120GL with an assortment of other fish that have never bothered him. Water stats are as near to perfect as I can get them and the only recent adjustment I've been making is the overdosing of flourish excel once a week to keep my Black brush algae at bay. Could this be causing the problem? none of my other fish seem to mind

Thanks
HAnk

 

[thegnu]

i had this with my male cockatoo. he was half of a breeding pair and he hurt his mouth after locking jaws with the female. he had a large white growth in his mouth that grew so big he couldnt close his mouth. i ended up netting him and cutting the growth out with a small sharp craft knife. it healed up perfectly but four months later i lost him when seemed fine

 

[Spank]

i had this with my male cockatoo. he was half of a breeding pair and he hurt his mouth after locking jaws with the female. he had a large white growth in his mouth that grew so big he couldnt close his mouth. i ended up netting him and cutting the growth out with a small sharp craft knife. it healed up perfectly but four months later i lost him when seemed fine

hmmm, I can't seem to make out any growth, but I'll have a closer look, when you cut the growth out did you just pin him down and cut? I'm all up for practicing my surgical skills (I'm a med student) and I can get access to sterile scalpels but I'm not so sure about cutting a moving/live fish.