You are going to have to provide more information if you want an answer.
Can you post some clear pictures and a short video of the fish?
What are the tank dimensions (length x width x height)?
How long has the tank been set up for?
What is the ammonia, nitrite, nitrate, pH & GH of the tank water?
How long have you had the fish for?
How long has the fish been acting weird?
Is the fish eating?
What does the fish's poop look like?
Is the fish breathing heavily?