I'm from the old school....keep your hands out of the tank as much as possible. I think putting your hands in the tank should only be done as a last resort. They sell all kinds of gizmos so you don't have to put your hands in the tank...those gizmos were not created because folks don't want to get wet.
Yes it does stress your fish...a big monster comes into their home and moves crap around. Fish designate territory, and use the rock formations to keep track of their world. LOL...Imagine if the houses and trees across the street and next door kept being put in different places...believe it or not you would be disoriented finding your own house.
We use that to our advantage when we get a mean fish defending territory...moving stuff around misplaces the thing he was fighting for. So if you are moving rock around to help the fish then great...but if you are moving stuff around to just change things up...stop it. That's just my opinion...I didn't read the links, and my opinion certainly isn't based on any scientific research.
It's actually dangerous for you sea critters to put your hands in the tank, there is stuff on your hands that can be toxic to fish and rinsing helps, but not as much as you would think. The lotions and other things you handle are deep in the skin pores....the longer you keep your hands in the tank the more of the stuff deep in your pores are released.
