it all depends on there personaluty,you could get a murderous demon,or you could get one like mine,who will only scare them away.ive got mine in with fish,and shes never killed any,even though they try to take her food.youve just gotta have a backup plan,in case yours gos on a murderous rampage.and keep in mind,most love to redecorate.they will move anything they can,so if you get one,i hope youre not to attached to your aquascaping.and remeber,lots of caves.