If your fish seem to be disappearing one by one, you probably have a predator problem. Here's what you need to know about Pond Predator Control.
Herons
The heron is a common pond predator. Herons love to snack on fish and frogs so if one discovers your pond it will likely return again and again to get its fill. A heron decoy can be an effective deterrent as herons are very territorial and will not invade another heron's feeding territory. There are also "scarecrow" mechanisms, motion-activated sprinklers that can frighten herons away, available.
Mammals
If you count your fish at night and then notice there's one or two missing in the morning, the chances are good that a raccoon is making a midnight snack out of your finned friends. If it's feasible to fence your pond in, that's a good way to discourage predators. For serious problems you may want to consider an electric fence. The scarecrow sprinkler is also effective for use against mammals, but its usage in winter is limited in many climates where the hose may freeze. Winter is an especially dangerous time for pond fish as the leaves of aquatic plants die down, giving them fewer places to hide. Cats, coyotes and other mammals can also pose a threat to your pond animals.
General Deterrents
Placing a net over your pond at night and when you are away will keep all predators out of your pond. Building a deep pond with plenty of plant life will give your fish a place to hide and retreat from predators.
