Paralized Panther Grouper

[swill]

We have had a panther grouper for about 8 months now. We got him quite small but is now about 6" approx. He's kept in our 300 gallon FOWLR tank. About a month ago we noticed him laying flat on his side on the bottom and breathing heavy. We figured he was going to die and left him overnight to see if he had become food for the rest of the tank. We woke up to him still in the same spot and when we fed the tank he actually ate. It was strange to watch though because he only ate when the food came to him, he didn't really get up or swim to the food, it floated by him so he grabbed it. After about 4 days of this activity we decided to take him out of the tank (mostly because he was now missing a small part of his tail)

He now lives in a 10 gallon with 3 tiny chromis (it's our sons tank and it was our only option.) He's been in that tank for about a month. He eats daily but only when the food comes to him. He is always laying flat on his side. I'm going to make a video and post it on youtube to show you what I mean. I am wondering if its possible he's paralized and if so what would have caused that and is there anything I can do??

TY