my yellowtail barracuda has been acting kind of funny he gets skittish easily and rests on the bottom alot and he doesnt really eat.he is about seven and a half inches long and he is being housed with the two red tailed payara one same size other a bit smaller and three masive 5-6 inch silverdollars i got him to eat a massivore pellet after a dozen trys and i even tried his favorite food cut silversides but he still wont eat wat might be going on and how can i fix it?water params are normal and everything leaves him alone do i need to get him some more barracuda freinds to keep him secure?also i have had him for seven years