My gf has a fat Ryukin. It's left fin doesn't seem strong enough to keep him straight. When it swims slowly its fine. When it wants to go somewhere quickly, he ends up swimming a tight little circle and goes nowhere. Between you and me. it's freakin hilarious.
There is a red welt right under the skin where the left fin and the body meet. She has had him for 2 months and has always been this way. He is a very happy fish and has a great appetite. He s also the largest and boss of the tank, so no one bothers him. Is there anything I can do to help heal his fin? Maybe this is the way he is now?