I have a Pinktail and Picasso Triggerfish. Before I bought them I removed, (I thought I removed), all the inverts such as clams, snails, crabs and so on.
Guess it goes without saying I saw a few peppermints run for their lives to no avail. I did manage to get a couple out at the last minute.
It's funny to watch the Melichthys indicus (Humu Humu Triggerfish) pick up shells and move them around. The teeth grow as they do and if I remember correctly, continue to grow partly why you might see some of this action in an effort to keep teeth normal. But, they will crack open a shell to eat a hermit or snail. It's not that they are entirely mean...Just hungry. Look how quickly they grow.
The older my Pinktail gets, the tamer she is. The older the Picasso gets...not the case. Just my 2 cents worth.