I tried a clown tang.
Failed. It was a quarter the size of my desjardini sailfin tang but instantly the boss. Everything else gave it a wide birth like it’s got death written all over it. It never asserted its authority, it was somehow known.
And yeah, as said, I had very high flow but these live in the shallows swimming through water that’s getting smashed against corals, my flow was nothing to it, and it slowly wasted away. It was eating, just not getting the exercise it needed to maintain its muscle mass.