well right now he is 4" and that leaves him 12 fish lenghts, no one was purchasing him at the lfs
and he was in a tiny compartment so right now he has a better home. As for a larger tank when he grows he will have one. I am going to be moving in a year so that will be upgrade time. If we are talking size to tank length ratio he has much more room now than he would full grown in a 6ft tank.
As for being agressive twoards inverts he is fairly peaceful, all he does is sometimes flare at the two ocellaris clowns. Though, I bet this depends a lot on the particular fish and its attitude. As for the duster I believe it blew its crown but is still in its tube, hopefully growing a new one.
55 gal FOWLR
Euro-reef 5-2 skimmer, 29 gallon sump
3x penguin 1140 ph
2x65 10,000K and 2x65 03
/30lbs argonite sand mixture
80lbs keys rock (www.liverocks.com
25lbs fiji/tonga lr
10lbs lace base rock (now hapily live with lots of coraline growth)