Not only did the plastic heron not discourage the real thing from helping himself at our pond, but it actually encourage him. Rich saw the real heron attempting to share a fish with his plastic counterpart. So it would now appear that the contents of the pond consists of Jaws and the frogs.
We spent yesterday morning putting the netting back to protect Jaws and the frogs. To make sure there are no frog spawn disasters (or similar) the netting is raised a foot above the water on bamboo poles.
There were a lot of frogs in the pond with Jaws, so it hasn't been for nothing. RIP little fishes for whom it was too late.
Some of the frog population
A ladybird which doesn't live in my bedroom!
The heron, still watching the pond