depends on the tank.
My native 40B tank is pretty inquisitive. my pumpkinseed usually attacks my hand because he thinks im holding food, my bluegill follows me around, and the darters all line up and watch me.
My gar tank...they drift around my hands but dont really go nuts.
my african/bichir tank...the loaches go crazy, the bichirs dont move, the butterfly fish zips around me, and the bushfish hide for dear life.