Great, The Mandarin will be happy.
PS--Nice fish.
Thank you. Also thank you for being worried about the well-being of the fish. I am very well aware of the difficulties in keeping dragonettes, especially mandarins, through the research I have done.
My other SW tank (75g) has two female scooter blennies which are still doing very good. They did have a little rougher start as I was unaware of them being dragonettes and not real blennies (same as mandarins are not gobies). Mainly they do graze around everywhere in the tank, but also learned to catch and eat shrimp when we feed - only when the shrimp happens to fly by at a slow enough speed and close enough to the surface.
My very early assessment: it is not enough to let a tank establish for X or Y amount of months and simply hope that the conditions are met (because hey, statistically they should). In the case of a mandarin that would be copepods that multiply faster than he can eat. Most success stories I have found (and there is much more failure than success I am afraid) have this in common: big tank, lots of live rock, refugium. There is that oddball report of mandarin accepting frozen food (very rare), and owners willing to supplement live copepods regularly (very expensive). My only realistic option to beat the odds is to have a big tank, lots of rock, a refugium. That was the easy part since that setup is beneficial not only for mandarins. Instead of hoping for hitchhiker copepods I cheated by collecting algae from other peoples established refugiums that already had a bunch of copepods.