Tiger oscar mouth always open, please help

[101films]

My oscars mouth has been stuck open for a while, I though it would heal but it’s been like that for at least 3 months. He still eats a little bit has also been acting strange. There is plenty of oxygen in the 55 gallon tank. What could I do to help him.

[Autumnsky]

I have had a couple times a fish with barbs or a rock was stuck in the mouth. Had to remove it.

What illness was it?

Do you know your water parameters, and do you know about the nitrification cycle? Link in my signature helps to make sure you keep good water quality, which is a top reason fish get sick or have problems.

[101films]

Well it can’t be the water quality because I’ve cleaned it multiple times while his mouth has been open and I have lots of other fish in their with him and their fine. The tank is kinda narrow I think around 12 inches wide but longer.