fungus or physical damage? help

[giar]

what is this? and how to treat it?

i have him with a 13 in florida gar, could it be the gar caused the damage?

 

[Wailua Boy]

I would lean toward physical damage

 

[Yuki Rihwa]

I would say physical damage too and FL is a trouble maker, they don't get along with any fishes and will always pick a fight even clearly they will lose the fight at the end. I would suggest you to remove either one to its own tank. If you keep them same tank then expect either the gar will slice the FL in half or you would get a broken snout Gar that got spook and slam to the tank wall at full speed.