HI bros
It is a 100% your fish have a tumor cancer inside the mouth as i can see in pic. i thought it happen to human being only but iam wrong, i think
there is no medication can cure this matter. to me once this tumor growth big and its willl then burst out and obviously your fish end up in dying.
your fish must suffering lots of pain in the mouth causing by that tumor,
that is why it having difficulties swallowing foods down.
cancer can be cure by the methods called radiotherapy and chemotherapy, but this only applies for human being and i doubt for fish though. there is a chance to cure its if you find out quickly. this sorts of illnesses (CANCER)if you leave it too long and there is noway you can do anything about but besides reducing pain if you using those two method above. but iam talking in real life, when human being having those cancer.
Anyway "THE TRUTH DOES HURTS" you cant runs away from it but only facing and accepting this sort of things.
SORRY to telling you all this, and hopefully your fish will enjoy the rest of his life with fully happiness without................
cheers................. and chill out is just a fish. when it come to human being then you start worry. if that the case,