You'd think, but if you ever saw one of these baby's in action at this size......I heard the undulated trigger is the meaneast/most agressive, I have a small one ( 3" ) and it's the most timid ( now ) hiding in holes in LR. Everytime someone walks in the room from 20 feet away this little guy runs for cover, you'd never even know he was in the tank. An eel may be compatible, lion fish don't do well with aggressive triggers, a ray ( now we're talking serious big tanks ) I don't know yet, but open to good ideas. It's almost like having a dog, he follows you when you get near the tank, eats from your hand, moves the LR around, it's a real trip.