i had a grey triggerfish once that was "curious" i was working on a power head and he came up and gave me a stiff nip on the wrist. i shook it off and figured he was just tasting me for fun. but then i was feeding him and a large piece of shrmp fel to the bottom. when i went to pick it up he latched on to me . when he let go i grabbed him and held him against the glass. after that he never bit me or tried to again. he was so tame he would eat brine shrimp from my hand and never even nipped me. i dont support " punishing" i support "Disciplining" but only if the fish is smart enough to "get it" e.g. cichlids and triggerfish, my oscar used to break my power head. when i would catch him in the act i would tap on the glass so he would stop. eventually he learned to stop. but as for the net shaking thing thats tottaly wierd.