I have been lucky, I know. I have a Humu Rectangle in the same tank with: 2 peppermint shrimp, 1 sallielightfoot, 1 skunk ckleaner, about 20 snails, 2 tiger serpent stars, 3 fancy brittle stars, 3 scarlett hermits. Trigger is only about 3.5" long and tank is 75 gal. I know one day he may turn and start killing things. But so far he is tame. One thing that i tried that seemed to work, when I introduce shrimp and snails I do it well after lights out when the trigger is about down for bed anyway. Gives the new guys time to get in the tank and finid a safe place without the trigger chasing them. If I can find my USB cord, I finally got a picture of the cleaner shrimp and the trigger interacting.