Birds are the worst enemy of your water gardens as they like to swoop down into your pond. Birds like egrets and osprey will wait until you are sleep, or away from your garden, to dive down into the pond and eat your fish.
You need to find ways to protect the fish in your pond. One way, is to dig your pond deeper. Birds want to stand in the water and catch their fish, and if you have a deep pond, then it would be difficult for the birds to stand in the water.
To read more Pests Attacking Your Water Gardens
