Bless you Roger and thank you for that
Roger, we made a frame last year to put the net on, a few inches off the ground, thinking it would be easier to put on and off but had to keep changing it as the plants grew, and the Heron still managed to get to the fish We tried the plastic Heron replica, but as it says on the RSPB site, that seemed to attract them!
This year we had the net on canes, like you suggested, but the Toads seemed to have a problem with it, even though they could get in the side they wanted to come out in the middle, hence the poor one we found tangled and dead yesterday.
I've seen photos of Karen's pond with bamboo canes that she leaves on all year, it is worth considering but it looks so much nicer without a cover on it!
In hindsight, we should never have put fish in and should have kept it as a wildlife pond but too late now we have them!
We've not seen the Heron this year, but I'm sure he'll come back if he discovers an open pond! I wouldn't mind so much if he just ate the fish, but some are quite big now and last time he raided it he threw 3 fish out and just left them as I think they were too big for him to eat!