There's Something Wrong With My Pleco's Tail!

[ashleighveronica]

I've noticed tonight that my pleco's tail has a blister on it and the skin surrounding the blister looks red and irritated. I've searched online for what it might be, but nothing matched the description. Can you help me?? i haven't had the best of luck with fish, but he's been with me for 2 yrs! HELP i just don't want anything to be wrong

 

[WILDER]

That looks nasty.
Is the gravel sharp.
How many gallons is the tank.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.
All you can do for now is issolate the fish and try a bacterial med for now.