Don't feed the tank for 24 to 48 hours and leave the net in the tank for several hours to get him use to it, then feed a little and see if he comes out.
I spent 2 hours once trying to catch a Cherub Angle, after the 1.5 hour mark, I was thinking of using the shop vac and suck the little *#@# out.... finally caught him after removing 80% of the rock!
Good luck!
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