I think the key is training them from an early age, my fish are not in the least bit phased. I do two water changes a week plus I'm in there nearly everyday replanting or messing with something minimal. They like it when the waters being put back, they will swim in the stream occasionally if im not in there watching.
I wouldn't however start training them that after the hands/hoses are removed food comes shortly after. They have bitten my air line clean in two and leave some pretty nasty marks in eachother. But on the other hand one day one of them wouldnt move so I pulled its tail, thankfully my dim witted move didn't cost me any fingers.
If anyone its my two convict cichlids that are the biters. I think I need chain mail gloves the next time something goes wrong in there.