Interesting that people have been keeping them safely in reef tanks. I just got back from snorkling at Ningaloo reef in Western Australia, and there were roving packs of them chowing down on various SPS corals.
Is the parrot getting to the clip at all? He looks like a spunky little thing! He'll need to be competitive to keep up with those big guys.
I'd recommend using multiple clips at the same time. Those bruisers are intimidating!
Are you feeding seaweed extreme pellets? He will still need an algae-based diet. I like to feed the purple Julian Sprung seaweed because of how readily it comes apart. It makes a mess but the smaller, less competitive fish get to eat it out of the water column while the big guys are preoccupied with the clip. Once the clip is gone (usually takes 1-2 minutes) they clean up whatever is left floating around.
Ooo, and extra large terminal phase male coming on LADD today. I'll be interested to see how it looks compared to mine.