Bishopbriggs resident Walter Morrison was shocked to find that the contents of his pond had been wiped out within minutes by a feathered fiend.
Witnesses told Walter that a 'giant bird' had swooped down and tucked into the fish – including Koi carp, which cost around £50 each.
He told the Herald: "My daughter happened to be looking out of the kitchen window at the time and saw this giant bird beside the pond.
"She said its wingspan must have been about eight feet. My neighbour also saw it and said it was huge and looked like a pterodactyl!
"I'd bought a plastic heron for beside the pond as apparently they don't go into each other's territory, but that obviously hasn't worked.
"I'd say all the fish cost around £300 in total so, after spending that amount of money, it is heartbreaking and I just want to let other people know they should be on the look-out."
The attack took place at Mr Morrison's property in Atholl Gardens last month.
Herons eat mainly fish, amphibians, small mammals, and occasionally birds.
They are solitary feeders and very patient, and will stand still for long periods stalking their prey.
They can quickly empty a garden pond of fish.