Sweet! I've had a few species that liked to be petted as well, namely a S.A. red tail, a leiarius pictus sail fin cat, a c. apurensis and an a. wittei giraffe cat. Most other species don't like hands and will dart to the other end of the tank as soon as they smell/taste a hand with a barbel. My red tail would like to be petted by me only, if someone else tried it she would swim away. I would liken it to the same way a dog knows friend from foe by smell. I wonder why Viktor would think petting fish would be controversial. The only downside I can think of is the possibility of overdoing it and perhaps removing some of the fish's protective slime coat therefore making the fish more vulnerable to infection? In my experience, never a problem and something to be enjoyed by the fish and their human...
