Honestly I had two, not together at the same time but both same size. They never had a problem with any other fish, never harmed/scared any of the small fish. Even when the other fish stole their food because they’re a little slower than my other fish they were pretty peaceful. I didn’t believe the whole trigger behaviors until my recent trigger gobbled my cleaner wrasse as a snack. I never had any issues with my clown triggers, can’t be a coincidence twice. I’d start with a small to medium size just to be sure. Even my current trigger is pretty peaceful, just happens to eat smaller fish or at least it happened once.