Provided it is kept in good conditions and fed properly its mouth should heal fairly quickly.
The singular possessive noun for the mouth of a fish is fish's mouth.
If you have a cut on the corner of your mouth that won't heal, you should see a doctor. They can determine the cause of the lack of healing.
You see a doctor and let it heal.
a bony fish's mouth is at the front of the body.
A mouth.
If you mean "Can a fish heal a cut?", the answer is yes.
heal
buy a new fish
A blister in your mouth that persists and does not heal may be a sign of oral cancer. Any sore that does not heal within 2 weeks warrants evaluation by a health care provider / dentist.
A Cary fish is a big fish with a big mouth to catch krill and small fish A Cary fish is a big fish with a big mouth to catch krill and small fish
You can catch a fish through its mouth
There is no way to heal it unless you have a Splash Potion of Healing/Regeneration. Although there is a rumor that you can heal it by feeding it fish after you tame it.