I think you'll be fine as long as you get a large enough puffer, as long as it isn't a bad fin nipper. Which most puffers i've see are. Remember your toad fish will just sit there all day and night, peaceful and quiet- until something swims in front of his face. I hardly ever see mine move, except to eat- and i would hate to put anything in there that would disturb him. Thinking now of adding one more eel and then letting them be.