How to Remove Leeches From Your Pond Without Chemicals
A Safe Pond for Fish and Wildlife
How do you get rid of a nasty leech infestation in your pond without using chemicals or killing all the plants and wildlife and starting all over? That is the question I faced recently when I saw some horrible leeches on my fish. I needed a safe way to remove them from my pond. If there is one creature that totally grosses me out it has to be the leech. They can't help it, but they are basically unloved and unwanted. The very thought of them should be enough to make you cringe, and there they were—on my fish. What could I do? What would you do to remove leeches from your pond?
A Simple and Natural Solution
Not everyone is confident in natural treatments for a start, but this is one that worked for me. It is all about caring for your fish in a more natural way. You can control a leech problem using natural methods!
How to Make a Leech Trap
If you want to go down the chemical route, it is complex and dangerous. It is also expensive to buy pond chemicals in the quantities needed. It involves replacing all plants, estimating exactly how much water the pond holds, and possibly harming smaller fish and killing every living invertebrate in the pond. That was not something we were prepared to consider.
So what is safe to use to kill leaches? I searched and searched until I found the idea of constructing a leech trap out of a coffee tin. Where I live, coffee tins are not so easy to find; they tend to be metallic cardboard. Then, I thought of fresh soup containers, and the leech trap was born.
Here is how to make and set your own trap:
- Plastic or metal container (I used a soup container)
- Sharp instrument (in this case, a steak knife)
- Bait (raw meat—I used kidney in this example)
Step 1: Bore holes into your container.
Step 2: Place the bait at the bottom of the container.
The leech trap works on the same principle as Winnie the Pooh and the honey jar: Leeches, being greedy, will gorge on blood, and when they do, they become so big that they get stuck in the container. That is the principle—and it works.
Step 3: Set the trap in the pond.
Use a net to lower the trap into the pond. It will fill with water and float upright. This will catch many leeches as they can sense the meat and swim up to it.
To sink the trap deeper, put stones in before the meat. Then, just leave the trap for a few days to a week. It will soon fill if you have a bad infestation.
The Trap Was a Success!
After One Day
After Two Days
He with a smile did then his words repeat
And said that gathering leeches far and wide,
He travelled, stirring thus about his feet
The waters of the pools where they abide
Once I could meet with them on everyside
But they have dwindled long by slow decay,
Yet still I persevere and find them where I may.— William Wordsworth, 1802
How We Determined There Was a Leech Problem
Shortly after my parents moved into the bungalow where I now live, they decided to dig a pond. They wanted it to be natural and encourage frogs and newts. My partner and I left some goldfish from the fair in the pond one weekend while they were away. My parents were delighted—and so were the fish—and over the next year or two, they were given ghost koi, shubunkins, and some golden orfe.
Frogs came to the lily pond and established themselves. The pond was kept fresh with a water pump, water soldiers, water snails, and mum's meticulous care, removing falling leaves and debris. The plants spread and the ghost koi kept the balance. Herons came and took some of the fish, but it was peaceful enough.
Chemicals were never used. Then, the remaining big fish died, one by one, and the last fairground goldfish, now huge, succumbed the week they moved into sheltered accommodation. I saw a leech on his body but assumed it was there due to his weakened state.
My partner and I redecorated, refurbished, moved in, and saw the pump was hardly working. It was important to fix this as it is the main factor in caring for the fish. At this point, the frog population was healthy, too, because it was before the big freeze. The week we moved in, we bought a pump with a water filter and UV light, intending to restock. We bought six comets and two green tench to join the little brown carp-like wild fish that we believed were the result of crossbreeding and reverting between shubunkins, goldfish, and ghost koi. We couldn't believe how clean the pond became within days.
One of the comets died—again we saw a leech, but didn't realize at that point that our fish were being attacked by leeches. We thought it was because it couldn't cope with the move.
Our Pond in MayClick thumbnail to view full-size
We were keen to restock our pond, so when the weather warmed up, we went back to purchase some ghost koi babies and some small shubunkins. There were fewer frogs due to the harsh winter, and we wanted to get things back the way they were. Little did we know of what awaited the new fish. Within days, we had to remove a comet for treatment because it had a leech attached. Then, one of the baby ghost koi died. That was when alarm bells really rang—leeches on pond fish are no joke!
What Is a Leech?
Apart from being gross, a leech is a water worm that belongs to the phylum Annelida, class Hirudinea. The blood-sucking parasite feeds on birds, fish, frogs, and mammals, including humans. Infestation by leeches produces a condition known as hirudiniasis. Not all leeches suck blood. Some are carnivores and hunt insects and snails. However, about 75% of known species of leeches are external, bloodsucking parasites.
Leeches secrete hirudin, a chemical produced in their mouth glands, which stops blood coagulation. Up to the middle of the 19th century, bloodletting by leeches was a common medical treatment. Medicinal leeches were sterile, but wild leeches could produce infection and ulceration when satiated as they drop off.
Leeches enjoy slow moving streams, ponds, lakes, and marshes and can live on moist vegetation in jungles and other humid environments.
Do You Have Leeches in Your Drinking Water?
This is a serious health risk.
Someone asked this question:
How do you treat a leech infestation in a pond that is your source of drinking water?
This is a very real problem! Drinking leech-infested water can lead to fatal illness. Leeches have been known to attach to the throat or mouth and suffocate the victim or cause internal haemmorhages (bleeding). If your pond is your drinking water supply, then you must treat it aggressively. Treat with chemicals, neutralize, drain, remove and destroy all plant life, and allow the pond to dry out completely for several weeks.
This will basically destroy all life in your pond. If you don't want to be so destructive, you are faced with two alternatives:
- Chlorinate your pond water with water treatment tablets and thoroughly boil it before use.
- Find an alternative source of drinking water. Purchase a watercooler or ask for the town water to be connected.
Some people have manicured ponds. Others like them to be as close as possible to nature. Do you have a pond? Have you experienced a problem with leeches? Tell us about it here.
Questions & Answers
© 2010 Lisa Marie Gabriel