Pond Problem Solving - Pond Predator Control

• Herons
• Raccoons
• Mosquitoes

Herons are a magnificent bird, standing about 3 feet tall with a wingspan up to about 6 feet, and they can wade in water as deep as 2 feet. They will eat anything they can swallow, including some fairly large koi. They are patient hunters, and they will stand still and wait for your fish to come to them. As long as they can feed from your pond, they'll return - and left undeterred, a heron will eat all your fish in a matter of days. Herons do not land on water, so it helps to make your ponds edge as difficult for them to navigate as you can. Their feet are adapted to wade in muddy lake bottoms - it's harder for them to walk on gravel or slippery rocks. You can use this information to landscape your own "heron barrier" around the pond - it will help, but it's not foolproof.

You can place netting over your pond to make it more difficult for a heron to walk in the shallows. Lightweight black netting is ideal - it is barely noticeable, and you will not have to keep it on forever! After the spring mating season is over, using a heron decoy may help. This is because herons are territorial, and they will usually stay out of other herons territories when not in search of a mate. Remember to move the decoy around occasionally to imitate the actions of a live bird. Otherwise, your decoy will become much less effective over time. Others swear that a scarecrow, since it mimics a person, is just as effective - and won't trigger a herons natural curiosity as a heron decoy can! A motion-detecting "scarecrow" can also be very effective for protecting your pond from herons, as it squirts water when set off. The good news is that it does scare off herons. The bad news, however, is that it will also squirt you - and your guests, your children and your pets. Depending on how close to your house or patio your pond is located, this may be very inconvenient! Don't forget your basics - building your pond with a "deep" section of at least 3 feet will help, as will providing shelter for your fish, like the easily installed koi kastle.

There are two ways that a raccoon will use to catch fish in your pond. If your pond has shallow edges, a raccoon will simply wade into the pond and capture your fish. If your pond has steep sides, a raccoon will sit at the edge and entice your fish to be caught. (This is especially true for Koi, which are very tame) Raccoons are nocturnal animals, and since they tend to do their damage at night it's difficult to catch them in the act of raiding your pond.

Raccoons are very smart animals, and fences, netting or motion-detecting "scarecrows" don't seem to deter them for long. Building shelter for your fish (depth, overhangs or sections of sumberged pipe) may help your fish, but raccoons can still cause other damage in your pond. The best results may be achieved by catching them in a baited "Have-a-heart" box trap and transporting them far, far away.

Let's consider something that may not be obvious at first: your pond probably reduces the liklihood of having mosquitoes in the area. That's because every mosquito that lays her eggs in your pond will not lay them somewhere else! Mosquito larvae need stagnant water to grow, and the combination of circulating water in your pond and hungry fish should take care of most of your mosquito problem themselves. Where you may have a problem is if you have a small water garden - with no fish and no water circulation. If that's the case, we'd highly recommend installing a small aerator or fountain to keep your water garden from becoming a mosquito breeding grounds.

For larger ponds, keep the following in mind: Avoid sections of "dead" water. Free-form pond designs are very pleasing, but when the skimmer is not located directly across from your waterfall, you may have surface areas on your pond surface with little or no water flow. If you do have a dead area, consider a small aerator - the air bubbles rising from the venturi will disturb the surface enough to keep mosquiotes away. Avoid extremely shallow areas in your pond. As long as the water depth at your edges is at least an inch, your fish should be able to snack on any mosquito larvae that do happen to find their way into your pond. Don't over feed your fish. Hungry fish make better mosquito predators! Consider building a bird house or bat box in the area. Bats especially are voracious mosquito predators! Keep your landscaping plants trimmed back from the water's edge - don't allow their foliage to grow over the water's surface!