mine does that all the time... he has a favorite leaf and if another fish comes near the plant... he swats it with his tail And no damage from any fish yet... just hair algae
Well, he doesn't appear to be "eating" the leaves, but he is going up and down them. What I'm worried about now is when he gets bigger. Going up and down those leaves when he is bigger could break them off at the stem.
I've heard that plecs can dessimate plants when they get bigger. I have a friend who's given up with plants because his 10" Plec will eat entire Swords overnight!! I guess it's the plants or the plec (when it get too large).
Hopefully by the time he gets that big I can buy a 125G and space out the larger plants enough with tall growth that he will have a hard time doing it.