Well, being an animal lover and especially a bird lover, I have a hard time thinking about 'killing' a heron who is just out doing what he does to survive. I don't think he wants to get too close to the pond because it's so close to the house, and there really isn't any place for a heron to stand and get to the fish (steep sides) Plus the fish have plenty of places to hide down pretty deep.
The heron has been here a couple times, but those pics were about five houses down, and there's a lake about a half a mile away so it's not like he's without food. I figure he just sees my pond as the proverbial "hole in the wall (ground) restaurant and wants to try it out.
Of course, I say all this having not lost a fish to one of these winged snakes...should I see him with one of my scaly children in his beak he will surely get pelted with rocks!!