Please HELP! Betta injury question
I rescued an Elephant Ear Betta from Petco 3 days ago. I say rescued because he had been at the store for over a week and had one blind eye which means no one was going to pay 20 bucks for him. I introduced him to a 20 gallon long tank, previously cycled (I moved my other fish to new digs). Water conditions are normal (0 ammo, 0 nitrite, 20 nitrate, ph 7.6, temp 78)
I have a penguin 150 on the tank with a sponge at the intake and a sponge at the top to deflect the current. I acclimated him slowly and he seemed like he was in heaven.
One thing I did not think of was that I had a rough aquarium decoration in the tank. First night went well, no issues. Something happen during night 2. I woke up this morning with an injured betta. One side is missing scales. The other side is also injured and he is not using his fun at all. He sits at the bottom of the tank. He did eat a couple bites - I waited until he floated at the top and tricked him into eating.
I am trying to attach pictures of the injury.
I immediately removed the stupid decoration. My question is: is there anything I can do to help him heal? I see no signs of bacterial infection but I am not an expert. This is my first injured fish in 5 years of having aquarium. That makes me lucky but also quite clueless. Tanks!!!