Great Blue Herrons - Ever watch a heron standing motionless on the side of a lake waiting for a fish to cross its path? If a heron discovers your pond, he will think he has died and gone to heaven. Unfortunately, that is exactly what will happen to many of your fish.

Herons are known to land directly in backyard ponds, even relatively small ones. It is not bad enough that they catch fish and eat them but they also poke and stab the larger fish and cause them to die a slow, painful death. A single heron can wipe out the fish population in a backyard pond in a single afternoon.

The key weapon in our arsenal against herons is to provide the fish with a place to hide that is out of the reach of the bird’s beak. A pond depth of 3 feet or more is often sufficient to prevent major fish loss. At least the heron will have to work for any fish that it catches and most will be wise enough to stay away from the danger if given a chance.

Another method is to include a hiding place such as a chimney flue pipe or culvert pipe in the bottom of the pond. The fish will quickly learn to dive for cover whenever danger comes near. The chimney flue pipes are flat so that they may also be used as a place to set plant pots in the center of the pond.

Raccoons -These masked bandits will come to your pond looking for water and a meal of fresh fish. It is nearly impossible to prevent them from getting to your pond in most cases. Therefore, you need to design the pond so that they cannot easily get into it and make a mess or eat the fish. The key is to design the sides of your pond such that they cannot reach the fish from the shore or from the plant shelf. Also, a depth of 2 feet or more in the center of the pond will limit their ability to reach the fish.