Poor guy.. he will make a full recovery.. perches are tuff, ask me I saved a 18"er(barramundi but still perch) a week ago while it was laying on it's side gasping for air.. Larger perches seem to be really passive but strong!!
As of this morning he is looking much much better. He has a brown "patch" on the top of his eye, but it appears to be getting better. All I'm using to treat him is very very clean water and salt. He ate like mad for the past 2 nights and already has his gut back
I might replace the 110 with a 150 (24" wide) and keep him by himself. He displays his colors a lot better now that he's alone.
I wonder if the loss of your Jag started the aro's aggression. Maybe he had to make a statement to the rest of the tank that he's in charge now. I've had community tanks go soar real quick with aggression when i removed or had lost a fish in that community. Hope all is well with your perch, and he has a speedy recovery.
ah he'll be right dude a bit of tlc and he'll be back...learnt quite a bit on hte nile perch watchingf this doco last mite...i never knew they ate baby nile crocs! hehe