So, you need to get rid of the water boatman in your swimming pool.
In this complete pest control guide, you’ll learn:
Why water boatmen bugs are in your pool
How to naturally get rid of them
Ways to keep water boatman bugs out of the pool
And more
By the end of this guide, you should have a solid foundation to control, manage, and get rid of water bugs for good.
Then you don’t have to worry about taking a dive into your pool anymore and coming up with a bunch of boatmen bites.
Sound good? Let’s “dive” in and get your pool free of water bugs!
Last updated: 12/10/19.
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What’s a water boatman?
These bugs are common in pools and ponds. (By Paul Albertella, CC BY 2.0.)
Water boatmen are common pests often found in pools and ponds. They sit at the bottom of slow streams or ponds to feed, breed and lay eggs.
They’re freshwater true bugs known as Corixidae and often fly around at nighttime seeking out water sources for food.
They eat plant materials by using their saliva to break down the plant and suck up the juices using a mouth tube. These bugs are harmless towards humans and don’t sting or bite.
Water bugs also have no known diseases that can be transferred. You’ll often find them skimming across the surfaces of water quickly and they can dive underwater to eat.
They’re almost similar to a water cockroach because their shape is so similar.
Other names
Boatmen bugs are also known as Corixidae, lesser water boatmen, Arcotocorisa arguta, Corixa punctata, pool water bug, and also often confused with backswimmers. Water boatmen and backswimmers are not the same bugs.
They have differences between their habits, appearance, environment, characteristics, and morphology. We’ll cover this later.
What do water boatmen look like?
They pretty easy to tell from other water bugs with their long, oar swimmers. (By Mick Talbot, CC BY 2.0.)
Water boatmen have a distinct, elongated shape that resembles a cockroach. They’re about ½” in length at full maturity with short front legs.
They have a shovel on their front legs that they use to scoop up food. The hind legs are miniature “oars” that they use to swim, similar to paddles used for boats.
They can fly and are often found during the night because they’re attracted to bright lights. These bugs swim right-side up with an air bubble they keep on their bodies.
This helps them keep afloat, which is how they swim across the surface of a pool or pond.
They can also breathe underwater using the air bubble, which is necessary because they lay their eggs underwater on hard surfaces. They’re dark in coloration, usually brown or black.
They prefer quiet areas of ponds, streams, and lakes where vegetation is diverse and plentiful.
Where do they live?
These water bugs are found in slow streams and ponds, often at the bottom scavenging algae and bugs to eat. They’re not found in shallow water, as they’re usually hiding under leaf litter or detritus at the bottom.
Most will just eat plants, but backswimmers (great boatmen) may be carnivores and eat smaller aquatic species, mosquito larvae, eggs, frogs, and even tadpoles.
Water boatman life cycle
Water boatmen have a simple life cycle. The adult female lays eggs in the water on a hard surface, which hat about 2 weeks later.
The water boatman nymph emerges from the egg and swims towards the water surface to get oxygen bubbles, which it uses to breathe underwater and swim.
Nymphs dart to the water surface more often compared to adults because they can’t hold their breath.
Over time, boatmen will mature and swim fewer times to retrieve oxygen. Adults are identical to nymphs other than size and a developed wingspan.
Nymphs will molt 3 times and grow wings as they mature. Each molt increases the size of their body, antennae, and other parts like their swimmers and wings.
Adult boatmen will then search for food and live out their lives in various stagnant or quiet ponds and streams. They’ll find food, mate, and lay eggs within pools and other water bodies.
What do water boatmen do?
Water boatmen are a common aquatic pest that almost looks like a floating cockroach.
They are one of the few species that only extra sap from plants and debris found in ponds, pools, and fountains.
They don’t really have any specific purpose. When you see them in your pool, they’re simply foraging or scavenging for food.
A few boatmen will eat other smaller bugs, but most will only feed on plants or detritus.
What do water boatmen eat?
They mainly eat plants and microorganisms such as algae and plant detritus.
Some will eat tadpoles, mosquito larvae, small fish, bugs, frogs, and other aquatic species. They’re used as pest control by some people because they keep all these other bugs out.
So they’re not all bad.
There are definitely some benefits to keeping water boatmen in a pond or other water feature. They eat many smaller invertebrates and have a rather large appetite for these bugs.
What is the difference between water boatmen and Backswimmers?
Backswimmers are a lot bigger and bulkier. They also swim with their hind limbs.
Water boatmen come in two forms- there are lesser boatmen and greater boatmen.
Lesser boatmen are the bugs that swim on their front limbs, and greater boatmen swim on their rear limbs. Greater boatmen are called backswimmers because of this habit.
They use their hind legs to swim across the water.
To add to the confusion, there is also lesser backswimmer, which is smaller than regular lesser boatmen.
Backswimmers are in a different family called Pleidae, while boatmen are in the Corixidae family.
To make it easier to differentiate between backswimmers and boatmen, here’s a list:
Boatmen
Lesser boatmen
Backswimmer
Lesser backswimmer
Greater water boatmen
Greater boatmen (backswimmers) are known to bite humans. It’s a painful bite, but not poisonous. Lesser boatmen don’t bite.
But people often confuse the two types.
How do water boatmen get in the pool?
Water boatmen will fly into your swimming pool because unmaintained pools often have growing or floating algae for them to eat.
These pests are carnivores but mainly feed on plants- meaning they eat plant materials and detritus like algae.
When you find them in your pool, they could be looking for budding algae on the surface of the water or on the edges.
Algae can be microscopic, so just because you don’t see it doesn’t mean there’s none.
Water boatmen get into your pool simply by flying. They have wings for flight and are capable of swimming and diving underwater by grasping an air bubble.
So they could be looking for food to eat or possibly scouting out an area to hatch water boatmen nymphs.
Do water boatmen fly?
Water boatmen can fly and are especially active during the night (nocturnal). They commonly fly near light sources found in ponds, streams, and pools as they scavenge for food and plant material.
Boatmen are attracted to lights during the night and hover around them as they search for food. You may find them at the bottom of your pond if you have an underwater light or surface light pointed into the pool.
Do water boatmen bite?
Backswimmers are easy to confuse with boatmen, but only backswimmers bite.
Lesser boatmen bugs are harmless to humans and don’t bite.
They’re primarily herbivores and only feed on plant materials and plant litter. But they will eat other aquatic species and larger backswimmers will bite humans.
Some species will eat other smaller bugs, but the majority only eat plants.
They have a soft tube mouthpiece that they use to suck sap and nutrients from plants and algae found in ponds and freshwater streams.
They spit on the plant to dissolve the outer layer and then use their straw-like mouth to suck the nutrients out.
However, backswimmers do bite. These are the larger boatmen. The bite is painful, but it’s not dangerous. It’s important to tell the difference between boatmen and backswimmers.
Backswimmer vs. water boatman bite
Lesser boatmen don’t bite, so if you got bitten by a water bug, you were probably bitten by greater boatmen (aka backswimmer).
They’ll bite if cornered, disturbed, or threatened. If you get bitten by a water bug, you’ll feel the bite and you may see swelling, rashing, or skin damage.
The bite isn’t poisonous, however, you should disinfect it right away. Consult a professional if you need one.
Are water boatmen good for my pond?
Water boatmen don’t really have any benefits other than eating up excess algae.
These bugs are very good fliers and will skim the surface of garden ponds, fountains, and small water features in search of algae. If your water is alkaline with lots of base nutrients, you’ll attract a specific breed of water boatmen.
There’s also an acid-loving species that prefer dense foliage.
Regardless of the water type, you have in your pond, water boatmen are easy to attract and may help control algae levels.
Boatmen bugs will also hover around rivers, streams, and other areas that are full of vegetation and plants.
How do you get rid of water boatmen in a pool?
Boatmen in the pool can be controlled by following some basic practices.
There are a few different ways you can manage and control water bugs in your pool.
All the methods really come down to maintenance and pool care. Here are a few of the basics which you’ll want to cover.
Keep your pool clean
You should be regularly skimming the pool surface with a pool skimmer and brushing the edges of the pool to remove excess debris and algae.
Spores usually hang out on the pool surfaces and stick to the edges around the perimeter of the pool.
You’ll want to remove these spores and any other plant materials that are just waiting to bloom.
This will prevent water bugs from being attracted to your pool because there’s nothing for them to eat.
Vacuum your pool
Use a high-quality pool vacuum and remove any debris from and plant materials that may be floating around.
Also, don’t forget to remove sinking debris that’s stuck at the bottom.
You’ll want to vacuum before you apply the pool shock and after also just to remove any pests that were killed.
Keep your pool’s pH and alkaline levels balanced
This means doing basic pool care like shocking, balancing the pool chemistry, and adding the necessary chemicals to keep your pH ranges in check.
Pool care is another subject entirely, which you should have some knowledge about if you own a pool.
Here’s an excellent resource that covers the foundation. You should watch your pH, chlorine, and alkalinity levels at all times.
Apply algaecide
Algae is what the bugs want to eat in the first place. If you use algaecide, you’ll kill off any spores or algae blooms.
This will naturally repel any water boatmen and keep them out of your pool since they have nothing to eat.
Use a pool cover
This will keep water boatmen out and keep your pool safe from sunlight, which will only make algae grow faster. A pool cover is a necessary purchase for any pool.
The cost will save you tons of time later on and prevents water bugs from getting no your pool.
You can also buy mesh covers if you want sunlight to shine through, but I suggest getting a standard, high-quality cover.
Clean your pump
The pool pump collects a ton of gunk over time from the moving parts necessary to function.
Clean it once a month to keep the pump working well and remove any algae buildup.
Replace the filters
The filters collect plant waste, pests, and algae over time. Replace them as necessary to keep debris out of your pool.
Filters that are not replaced can become a harbor for bacteria and microorganisms, both of which can attract water boatmen and backswimmers.
Pool lights are only on at night, and they’re a bright source of light directly in their favorite place to hang out- a body of water with plenty of algae.
So if you turn off the lights, you already eliminate one main attractant. This will help naturally repel any water bugs from landing on your pool water.
This is also one of the simplest and fastest ways to get rid of boatmen bugs in your pool.
How to beat the water boatmen in your pool
If you can’t stop them because there are too many, start right away by using a powerful algaecide to rid the algae.
After that, skim and vacuum the pool to clean it up. Use a pool cover and don’t swim in it for 7 days. This will starve the algae that remain and also kill off many other plants and microorganisms.
After this, you can take the cover off and shock, skim and vacuum the pool once again. Leave the cover off and see if the water boatmen continue to come into your pool.
Keep the pool lights off at all times. If you can’t beat the water boatmen in your pool, consider hiring a professional at this point.
Water boatman predators
There are some natural predators that eat water boatmen.
Some of the most common predators are frogs, toads, fish, spiders, birds, and dragonflies. There are also some other water bugs that eat boatmen!
For backswimmers, some animals that eat them are large fry and some bigger fish.
There are also avian predators that scoop them up from above and larger frogs and toads that’ll eat backswimmers.
Water boatman sound
Water boatmen actually are able to emit a sound from the bottom of a freshwater pond or stream.
This produces a high-pitched sound that lets nearby females know of his presence, which happens before mating purposes. This is extremely loud for such a small bug!
If you ever wonder “what does a boatman sound like?” this video clip will show you exactly the sound they make:
By Sophie Pavelle.
Further reading and resources
And here are some handy resources that you may find useful:
Currently an active researcher in the pest control industry for the past 8 years- with a focus on using natural and organic methods to eliminate pest problems.
I share handy DIY pest techniques I come across here to help out others (and possibly save them from a mental breakdown).
Hi, I would be interested in knowing how you got rid of the flies!