Shy tang

[Proteus]

About 8 weeks ago I picked up a Freckle face tang. He/she was about 3" when I got him. And typically hid. But 8 weeks later still hiding. Only coming out during the evening as long as he can't see me and even then only to bolt to the grazing puck then back into his hole.. He has grown substantially around 5/6" now and looks quite healthy.. Only other fish in tank are yellow assessor and rankles assessor. Tank is 6'x24".

Any way to make him more comfortable to swim in open