Predators And Your Pond Fish

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Written By Mark Washburn

Mark has 20 years of experience as a professional pond management consultant.

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Grizzly Bear (Ursus arctos horribilis) catchin...

Some things just like to eat fish.

Take the Grizzly Bear for instance.  There’s nothing quite as wild and dynamic as watching a big Kodiak dine on salmon in the Alaskan wilderness.  It’s nature at it’s best.

But it’s a different story when the wild, and sometimes not-so-wild creatures start visiting your backyard fish pond.  These uninvited guests can cause a lot of havoc on a Koi or Goldfish collection and it’s quite disheartening to see fish disappear, day after day, until there are few, if any left.

Threats can come in all shapes and sizes, however you have my deepest sympathy of all if you do have to fend off the aforementioned big bear.  Most of what pond owners in the lower 48 have deal with aren’t quite as large, but they can be just as damaging to fish.

Avian Predators

From the air we can include, primarily migratory wading birds like Herons and Egrets.  Ospreys and Eagles, which are birds of prey, generally won’t bother a smaller pond but may take advantage of fish swimming in a lake or river.  So let’s focus our attention primarily on the first two birds mentioned.

Both Herons and Egrets are wading birds and while they can handle a bit of depth to the water, they don’t like to go too deep.  Herons being larger can likely handle depths of up to a foot to maybe two feet but that would probably be pushing it’s limits.  Egrets would be about half that before they start to get really wet.  So rule numero uno is to have some depth in the pond if possible.

Depth is good for a small pond and fish in many ways, but suffice it to say,  if they can go deeper, they will usually be safer.

Netting of various kinds, as well as fine line, strewn over the pond in a grid pattern has also been shown to be a useful deterrent because the bird’s can’t walk or wade around very easily, and in some cases, they can’t even get much of a foothold in the water.  If the line is elevated higher, it may hinder some of their wing flapping during landing and deter them that way as well.

Devices such as flash bulbs, aluminum foil, sprayers, and decoys have historically had mixed reviews but are worth trying.  In some cases, for example, decoys may help keep a bird away,  but much depends on the time of year that they’re deployed.  Although these birds are solitary by nature, at certain times of the year they’ll be about a social as your favorite chatty aunt who likes to go to bingo games on Friday night.  Decoys may even draw them  in during the breeding season, so beware and test this strategy out before leaving things unattended.  Motion sensing sprayers and flashers can also sometimes help.  Herons can learn quickly and while most birds may be deterred and agitated enough to leave, some may discover that no harm really comes from all the hubbub and stick around.

Keep in mind, like any other predator, wading birds are opportunists.  Make it a little bit tougher in various ways for them to get  an easy meal and they may depart, frustrated and hungry.

Land Based Critters

As the years go by and we hear feedback from more pond owners, it’s amazing to listen to their stories of enemy infiltrations.  It’s long been known that animals like Raccoons and feral cats can cause some problems.  A friend of ours actually found a dead and drowned Raccoon in her plastic lined pond and it was a big fellow too.  He apparently went in wading after a fish and couldn’t get out due to the slick side walls.

Other additional intruders include Fox, Mink, and possibly other larger carnivores like Coyote or Black Bears.

Keeping some of these guys out of a pond can be a real challenge.  Some are either small enough to get through netting, or big enough to not even notice it or be bothered by it.  As with the birds noted above, deterrents may work for awhile but often the critter will adjust to it, or figure out a way around and still get to the fish.

If you’re really game to try something you could put up a small electric fence line around the pond and this might provide enough of a jolt to ward off any interested feeders.  Just make sure you don’t get shocked too!  In some states and locals, trapping and relocation may be possible but you’ll want to check with your state game officials on that one.  In certain parts of the country such activity is deemed illegal and no animals can be harmed, relocated, or dealt with in any way.  (I know it’s crazy to hear this but please, don’t shoot the messenger!)

A Good Defense Usually Wins

I’ve heard this applied to winning football games, but the term could also be applied to fish protection.  A good defense will be hard to beat.

I mentioned depth being an asset above, but there are other things you can do to help your fish survive an attack.  The key is really to provide them with adequate protection, and it could be said that proper training fit’s in here too.  First of all, think a little bit like a hunter when you start putting rocks and things around the pond edge.  Look for where a fish might be vulnerable and try to incorporate some overhanging flat stones and don’t allow easy wading into the water if possible.  Shear drops are good for this, or at least creating a shear drop with surrounding material is helpful.

Protection at the bottom of the pond can come in several forms but one of the most useful and sturdy additions is a koi hut or tunnel.  These are normally made out of plastic and they provide a secluded and protected place for fish to hide if they have to.  There are times of the year when these devices will help minimize stress, even if you’re not on the immediate menu, and during times of attack, they provide a great hiding place.

Adding desirable surface plants such as floating lilies, or incorporating duckweed and other “coverage” vegetation can provide some natural protective, and concealing cover that fish can  use to avoid detection in the first place.

Many fish eating birds, and thankfully many smaller mammals don’t really care for the presence of a larger animal nearby, so if you have an able bodied, hairy member of the family, and by the way, I’m talking about the canine variety and not your spouse’s burly and bald cousin, the very presence of having a dog nearby will keep a lot of trouble makers at a distance.

Before we go, let’s talk a little bit about fish training and how many people may, inadvertently be setting their fish up for a bad time.

Most of us really like to feed our fish, and we take great pleasure of connecting with our finned friends through hand feeding.  I’m not going to stand here and tell you not to do it, but I will remind you that this type of “training” may come at a cost.  Fish are wary at first, until they are taught otherwise, and when they are rewarded for coming to the surface and feeding from the hand, it’s not unusual for them to come up, lured through the Pavlovian response, and end up as the meal instead!

So if you really want to protect your fish, don’t make feeding a spectacle.  Keep it as low key as possible and don’t train them to feed from the hand.  Ideally you want a fish to move away from some unknown thing a long the shore line…the curious one’s may not last long.

When all is said and done, there are many things you could try to keep your fish safe.  The types of predation will vary a lot and in some cases, they can be very hard to stop outright.  Setting up deterrents of any kind (keep it legal) may be helpful and are worth trying, but perhaps the best options you’ll have will be in, on, and immediately around the pond.  Anything you can do to make life just a little bit harder for an opportunistic thief will be a step in the right direction.

Do you have personal experience, and more importantly success in protecting your fish from predators?  Please share your thoughts below…



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2 thoughts on “Predators And Your Pond Fish”

  1. I use a motion sensor water spray, and the heron and egrets have disappeared. So have the salesmen as they attempt to get up to the front of the house! Great tool!!

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