One of the major problems when owning a fish pond full of Koi or goldfish is predators, especially herons, they fly down, wade into your pond, snatch your fish, swallow them there and then or take them away to eat later.
You can’t blame them, they are predators by nature, this is how they feed themselves, you just wish they would do it elsewhere and not in your pond.
Herons are very persistent birds but they can be deterred.
In this article we are going to look at deterrents to help keep your fish safe from herons and also give you some facts about the feeding habits of herons.
Why do herons attack garden ponds
They don’t just attack garden ponds, they will hunt wherever they can find food.
In their hunt for food they can travel vast distances, so a visit to a garden pond is not uncommon.
The fact that garden ponds are small, compact and full of fish compared to its natural hunting ground like big lakes, rivers and canals just shows you why a pond is very attractive to herons.
When do herons attack garden ponds
Herons usually attack ponds just as dawn breaks in the morning and at dusk in the evening.
As they get to know your pond, they will get more and more confident that it’s a safe place to fish, so they can start attacking your pond throughout the day.
They hunt all year round, but during the winter when your fish move to the deepest part of your pond the heron will stop attacking your pond and feed on land based prey.
Do herons fish at night
Although herons don’t usually fish at night there is a one time of the month that they have been found to fish and that’s around the full moon.
How do I know a heron has attacked my pond
If you have noticed some of your fish have gone missing from your pond you need to look for tell-tale signs of a heron attack.
Look for feathers in and around the pond, broken plants where a heron would naturally wade into your pond, torn netting and fish that have been attacked and injured but luckily got away.
If you find one or more of the above it’s more than likely your pond has had a visit from a hungry heron looking for a meal.
How many fish do herons eat a day
It depends on the size of fish, an adult heron can eat around half a kilogram of food per day.
Fish weighing around 200g are the perfect size for a heron, so two to three fish a day would be about right.
Do herons hunt alone
Yes herons do hunt alone, they are very territorial birds and will have their own hunting grounds that they like to stick too.
They are also very solitary feeders and don’t like eating if there are other herons close by, they would rather avoid getting into a fight for a fishing spot, that being said if they are very hungry they would take a chance and land near another heron to grab a bite to eat.
Do herons land in water
No they don’t land in the water, they land on solid ground around your pond and wade in.
They are not like seabirds that dive into the water from flight.
How do herons take fish from ponds
The heron wades into your pond to take your fish, it stands perfectly still waiting for a fish to go by, at this point it will strike out with its beak killing the fish.
Once the fish has been killed the heron will eat it whole or grab it with its claws and fly of to eat it.
How deep does your pond need to be
The deeper your pond is the more your fish will be protected, anything less than 24″/600 mm deep is very inviting to a heron, most will hunt in waters that are no deeper than about 18″/450 mm, so don’t make it easy for them.
The deeper the pond the safer your fish are going to be. Having steep sides to your pond also hinders the heron as they like shallow water to wade into.
If you have not yet built a pond and are worried about herons choose an area near to your house where herons are less likely to come.
If this is not possible or you already have a pond thats away from the house try to make it with vertical sides or use lots of shrubs to stop the heron wading in.
Are herons protected
Yes, grey herons are protected under the UK Wildlife and Countryside Act 1981, blue herons are also protected in the United States.
Killing herons can incur hefty fines and even a prison sentence, you have been warned.
What is the best heron deterrent
Below is a selection of deterrents to keep herons away from your pond, you might find that just one of the deterrents works for you, but if you have persistent heron attacks you might want to try a mixture of deterrents to protect your fish.
Do plastic heron decoys work
Heron decoys can work for a short period of time, the heron flies over your pond and spots the decoy, it thinks it’s another heron and flies on.
After a while the heron will cotton on that this decoy is not the real thing and will fly down to investigate.
One way to confuse the heron is to move the decoy around your pond every day or two, this will give the impression that the decoy is alive, but herons are clever and will eventually ignore it.
Sometimes it has the opposite effect, especially during matting season, the heron will be looking for a mate and will think your decoy is the perfect partner.
If the decoy is smaller than the heron that wants to go fishing in your pond it might come down and challenge the decoy.
A heron decoy, even if they don’t work is a nice addition to your garden pond.
There are plenty of heron decoys for sale at amazon.co.uk
The fishing line method is well know and used by many pond owners. It relies on strong fishing line being strung back and forth across the edge of your pond were a heron would normally wade in.
Having the fishing line criss-cross at different heights is the best way to set it out, the heron will walk into the fishing line and won’t be able to work out how to get past it, it gets baffled, frustrated and panicked, eventually giving up and flying off, plus at the same time the fish will be alerted to the noise of the heron and will take cover in the deepest part of your pond.
Fishing line is not that visible but it still shows up and can look a bit ugly, on the plus side it’s very effective and it’s cheap.
Floating pond plants
Floating pond plants give protection to fish when a heron is about, if the fish are swimming under the plants the heron won’t be able to see them, a heron can’t hunt what it can’t see.
The only problem is, as soon as your fish swim away from the plants and into clear view of the heron, it will strike.
If you have Koi you might find they eat a lot of floating pond plants and in doing so will give clear view to the heron, using floating planters will help stop your Koi from eating your floating plants giving more protection from the herons, plus the floating planters can be positioned in the area where a heron is likely to fish.
There is a drawback to this method, if your heron can’t see your fish to hunt them neither can you.
Air stones and aerators are an effective way of protecting your fish from herons, the water movement from the bubbles coming to the surface from air stones will hinder the herons vision and it will not be able to see your fish.
You only need to have the air stones near the shallow area of your pond where the heron would naturally wade in, but having them all around your pond limits the heron’s ability to see your fish when flying above, air stones are not only good as a deterrent but are good for your pond, supplying extra oxygen.
A fountain does a similar job by adding movement to water, often the heron will fly past your pond if it can’t see your fish.
Have a separate switch for your air stones, this is so you can turn them off when you want to observe your fish, just remember to turn them back on when you leave the pond.
Sounds like a strange sort of deterrent but dogs that bark at at the slightest movement can be a great deterrent.
Obviously your dog is not going to be in your garden all day long protecting your fish, but if a heron has visited your garden on several occasions and been chased of by your dog barking and chasing them on each occasion it’s going to deter them returning.
Tunnels and caves
A cave or a tunnel built into the design of the pond is a safe place for your fish to go and hide.
If you have a pond without a cave you can buy a koi kastle, or build something similar, these can be placed into the bottom of your pond after the ponds been built, they are also a great place for your fish to shade from the sun.
Sound in your garden will put off a heron visiting your pond for a spot of fishing, if it thinks there is someone or something that could harm them they will fly on.
Using a radio set to a talk show is a great way to deter a heron, the sound of people talking is a real put off, and they will keep well away.
Wind chimes are another source of deterrent that use sound to deter herons from visiting.
As long as there is wind they do have an effect, the best ones are the shiny ones that give of a reflection and twinkle in the light.
A motion sensor sprinkler is one of the best deterrents when it comes to herons, in fact it’s a good deterrent to all predators that fancies a fish meal.
They are simple to use, just connect a garden hose pipe, the sensor will detect movement and shoot out a sudden and startling jet of water for a couple of seconds, this is enough to send the heron packing.
Just remember they are a motion sensor, so there’s a good chance your’e going to get a soaking at some point.
There are plenty to choose from at amazon.co.uk
Putting netting over your pond to protect your fish from herons is in my opinion the best solution, that said it’s probably the ugliest solution, you want to see your fish swimming around in your pond rather than looking at them through some sort of netting.
If you do go for netting make sure it’s well above the surface of the pond, if the netting is too low or floating on the surface the heron will still be able to attack and kill your fish through the netting, it won’t be able to take your fish away, but you still end up with dead fish.
Having netting covering your pond does have its problems, it hinders pond maintenance and feeding your fish, marginal plants are also likely to get caught in the netting if the netting is not high enough.
Have a look on amazon.co.uk to see what’s available.
Pond floating guards
These are floating discs that float on top of the water, they look like spider webs, you clip them together until you have covered your pond.
The idea of this system is the heron will step onto the discs, the discs will wobble on the surface and the heron won’t be able to stand on it, they will get frustrated and fly off.
One problem with this system is you will have to clean them on a regular basis as they can collect a lot of plant detritus.
Check them out at amazon.co.uk
Fencing around a pond has two benefits, it stops the heron from wading into your pond and protects young children from accidentally falling into your pond.
You only need a small fence, we are not talking about a big fence, just big enough to stop a heron stepping over it, but it does need to be close to the edge of your pond, if you leave too much ground between the fence and the water the heron will use this bit of ground to land on.
Landscapping with plants around your pond can have a good effect, the foliage can limit the access to your pond.
Herons are a cautious bread, they would rather have a clear area with no planting to get access to your pond, and a quick getaway once they have caught your fish or are disturbed.
The right plants will not only protect your fish from a heron attack but also enhances your pond.
Pond dye is an interesting approach to deter herons from catching your fish, the idea is it creates an illusion that you have a deep pond plus it will be harder for the heron to see your fish as it flies overhead.
An electric fence is another alternative for protecting your fish from a heron attack.
It’s not something we would recommend especially if you have pets or small children, but they can be effective.
The electric fence will give a small shock every time the heron touches it, it’s not a dangerous shock, just enough to tell the heron to go elsewhere to fish.
There’s a good selection on amazon.co.uk
Placing mirrors around your pond has its benefits in the fight against herons stealing your fish.
When they see their own reflection in the mirror they think there’s another heron in the vicinity and will often fly off to avoid confrontation.
Position the mirror on the opposite side to where a heron is likely to land and wade into your pond, as the heron moves its reflection will move giving the impression that there’s another heron.
These are great for smaller ponds as you would only need a small mirror in the optimum position, for a large pond you would need a very large mirror or a selection of smaller mirrors doted around your pond.
If you see a heron in your garden the best thing to do is run at them with your arms flapping, show them who’s boss.
Shouting at them does work, but use simple terms like “Hey” rather than using long sentences like “get away from my fish you little ba****d”, this seems to work best.
Plastic alligators that float in your pond are designed to scare the heron, they have been known to work, but just as the plastic heron decoys herons can get used to them.
To be honest they probably wouldn’t work that well in the UK, alligators are not native to this country so are unlikely to deter a grey heron the same way it would a blue heron, that being said anything that a heron is not expecting could be a deterrent.
You can buy them as just a head or full body, place them in the shallow water where a heron is likely to wade into your pond for best results.
As with plastic heron decoys, these alligators are an interesting addition to your pond, having a head poking out from pond plants would spook anyone.
There’s a good assortment on amazon.co.uk