Welcome to the community.
What are the water parameters?
How long has the tank been set up? What size is it?
It is very difficult to take an injured wild caught fish and keep it in a tank situation.
These fish are used to eating wild fresh live food. Are you able to provide that? Frozen would be the next option, but could take time to get the fish used to that type of food.
Knowing the variety will help decide what kind of diet it should have. It maybe better to return it to where it came from.