Fish Caves: A Way to Stop Birds from Eating Your Fish

Isn’t it nice having a place where you can escape? Whether it’s by your pond, in your car or in a quiet bedroom, you always know you have a distraction-free space to unwind.

This kind of shelter is even more important if something’s always trying to eat you.

Fish caves are a great way to protect your koi from predatory birds, as well as keep them sheltered from winter cold and other stressors. You can either build fish caves into your pond’s design – they’re a standard part of the Splash Ecosystem Pond – or purchase them post-construction.

Let’s learn a little more about why these simple structures are so important to your pond life …

At a Glance: Fish Caves for Ponds

- Fish caves protect your pond life from predatory birds and give them a place to gather in the winter.
- Fish caves are part of any good pond design.
- If your pond was designed without fish caves, you can buy simple plastic shelters to keep your fish safe.

What’s Eating My Pond Fish?

Have you ever heard of fish in a barrel? A fish in a pond is almost as vulnerable.

In the wild, fish like carp – an ancestor of koi and goldfish – often have dull brown or gray scales that help them blend in with their surroundings. Domesticated fish have largely lost this camouflage thanks to selective breeding that brings out bright colors like orange and yellow.

These beautiful scales make koi and goldfish perfect targets for predatory birds, as does the clear, shallow water in most man-made ponds. Pond owners in Pennsylvania and Maryland can often blame birds like heron, hawks, egrets, opsrey and bald eagles when fish start to go missing. Raccoons, cats, foxes and other non-flying animals also sometimes dip into ponds for a quick snack.

Using Fish Caves to Protect Your Pond

If you’re in the process of building your pond now, or you’re interested in remodeling your pond, make sure to incorporate one or more fish caves. A fish cave is simply a nook or cranny in the bottom of the pond where koi and goldfish can go to be safe and happy in the winter, as well as to hide when predatory birds swoop overhead. When built into a pond’s design, they often look like natural rock overhangs, similar to what you would see in nature.

If you own a pond that doesn’t have a fish cave built in, you can buy inexpensive plastic domes that serve the same purpose. These lightweight structures simply sit in the bottom of your pond. All you have to do is weigh down the sides with rocks and gravel.

In a larger pond, having two or three fish cave areas would be ideal. In a smaller pond, we recommend creating at least one area in the pond where the fish can hang out. We always find it amazing how tightly the fish can pack together.

What If Fish Caves Aren’t Enough?

Fish don’t spend all their time hanging out in caves. So how else do we keep predators away from our fish? You have a few options. We’ve found here at Splash that motion-activated deterrents – called Scarecrows – that spritz animals with a short stream of water often work best. These devices have to stay connected to a hose in order to work, though – not a huge help during winter weather. Floating alligator decoys, which bob with the flow of your water, also work well for some pond owners.

Then there are the “solutions” that do little to solve your problem. Stationary decoy heron are among our best-sellers when it comes to predator solutions, but real birds usually catch on pretty quickly that this newcomer to their turf can’t hurt them. Fishing line also doesn’t usually work, with birds just stepping over it to get what they want.

At the end of the day, your best bet for protecting your fish is to experiment with different predator deterrents until you find one that works best for your pond. Your first line of defense, though, should be to make sure your fish have a safe cave or two in your pond where they can protect themselves.