How to heal injured clown knife fish help!!!?

I have just bought a clown knife for a flowerhorn's tankmate because the flowerhorn has a Iridescent shark tankmate and are doing all fine. But when I put the knife fish in the tank I saw the flowerhorn chasing the knife fish until I saw some of the knife fish fins are been bitten and its body has a big bite mark with its flesh seen I have put him in my planted tank with no fish what should I do to heal him and what should I do because my mother bought me 5 neons and 5 zebra danio where should I put them? so I use a fish tank divider