He has the goldfish in there for pirhana food! I'm not sure but my guess is he would just put his hand in there to clean the tank, most pirhana keepers do.
I always stuck me hand in the tank when I cleaned it. Pirhanas are shy. Mine would hide in a corner.
He would also not eat when anyone else was in the room. I fed mine a goldfish every other day.
I would like to get some again, but my wife will not let me. I'm getting my tank ready for 2 Discus. I should be getting them tomorrow.
Odd....my P's come right up to me....kinda scary ....glad I have a mag-float and python to clean this tank....otherwise I do believe there would be a little less of me every time I did it....