Your tank is plenty big enough for him and a lot of other stuff. A lot.
But the fish can grow up to 10" if you even have 1 for that long.
Someone that kept one that long would have an interesting/possibly challenging mix of other tank mates with it. Not really good for a reef style tank.
The fish being a larger wrasse is also not good with any inverts. (Even many small "reef safe" wrasses will go after very small inverts) A full size Lunare could even challenge a small - Medium sized Lobster.
They may leave some corals alone. They will eat a lot of different things. Many people find certain corals munched. Overall it is known as not reef safe.
For multiple reasons. From invert to coral damage, and a cumbersome large body size(one day) mixed with their high speed- that can be disturbing in a reef to it's other inhabitants.
Even at smaller sizes this wrasse can consume foods offered to the tank FASTER than many other fish can even keep up with it. Which can cause a problem, no matter how much you feed, to some other species to slow to compete. Some fish can suffer.
It's best with not too aggressive tank mates(so the Lunare is not hurt)
But very boisterous themselves, so they are not beaten out by this wrasse.
In the food chain and aggressiveness. You may not notice all these things now, he is small right now. But believe me, this fish is too much competition in a reef style tank. Shy fish don't do well with it. In the other spectrum It's even faster than most Tangs too!
It's hard to keep it with aggressives in the beginning when small in some cases. You don't want tankmates that can swallow it either obviously. But eventually when large enough, it is really best kept with some what more boisterous fish, slightly more sub aggressive to aggressive in a non reef setting. A lot of these types of tank mates are not all usually kept in Reefs either.
Yours not running from you is not out of the question either.
Go after it with a net though. I bet you won't even get close.
More than one attenpt will most likely start him into hiding in the substrate too. Burying himself. A tactic they use when threatened.
Also, you may never notice. But in the dark of night when they are done with activity at some point, they even "like" to go to bed "so to speak" buried in the substrate somewhere.
Sorry, this sucks. Believe me, I'd like to give better advice in catching. But most likely, your going to have to remove rock and sift the bottom.
One thing you can try is try tricking with some food and netting fast at the top. Try to keep the net close but hidden kind of some how. Use a non sinking food attractant. You'll have to be lightning fast and most likely it won't work.
