whats the trick to not getting bit??

lately my niger trigger has became rather aggressive every time i put my hand in the tank he tries to get me, he's fine with all my other fish as well as my CUC, other tank mates are 2 clowns, yellow tang, starry blenny, 2 chromis, 3 stripe damsel, flame angel, purple pseudo, assorted hermits and snails, brittle star, sebae nem, rose bubble tip nem, this is my favorite fish but im now considering getting rid of him ive had him about two years never had a issue till i upgraded to a 240g (he was in a 90g) a few months ago. is there a trick to keep from getting bit when i put my hand in the tank?