List of Common Aquatic Pond Insects (Pictures & Identification)


Pond Informer is supported by it’s readers. We may earn commission at no extra cost to you if you buy through a link on this page. As an Amazon Associate we earn from qualifying purchases.

Help Spread Pond Keeping Knowledge!

Aquatic insects are an essential part of a balanced water ecosystem, and the ones that are present can tell you a great deal about your pond and how healthy or unhealthy it is. For example, dragonflies are sensitive to pollution and therefore tend to be found in areas with good water quality, while leeches and mosquitoes are pollution tolerant, meaning that if they’re around, there’s a chance that your water needs some TLC.

Biologists often catch aquatic insects in water to deduce how healthy that area is, while of course performing other tests such as measuring oxygen and nutrient levels. This makes them exceptionally useful bio-indicators in freshwater ecosystems.

In addition to indicating water quality, aquatic insects also perform a variety of functions for your pond. Some will feed on other insects (for example, dragonfly nymphs have been known to eat mosquito adults and larvae); others consume algae and parasites; most can provide food for your fish, turtles, frogs, and so on; and some, such as caddisflies, help break down dead and decaying matter that might otherwise build up. While insects are often viewed as somehow undesirable, gross, or frightening, the reality is that there are millions of species of them, and their place toward the bottom of the food web means that they are relied on heavily by everything else – even us! Insects enable life as we know it, and are just as important in your pond as they are anywhere else. Here, we will cover insects that are found directly in freshwater ponds as well as those that live around ponds but are not necessarily in the water.

SaleBestseller No. 1
AmScope 120X-1200X 52-pcs Kids Beginner Microscope STEM Kit with Metal Body Microscope, Plastic...
  • Beginner compound microscope provides high magnification for educational applications
  • Monocular viewing head with LED and mirror illumination and built-in color filter wheel
  • Forward-facing rotating turret provides 120x, 240x, 300x, 480x, 600x, and 1200x magnifications

What Water Insects Can You Find in Ponds?

1) Mayfly Larvae

Mayflies have short life spans and indicate a healthy pond
Photo by Ian Alexander. Available under a Creative Commons Attribution-Share Alike 4.0 International license.

Mayflies begin their life cycles in water, where the mother lays her eggs on the surface and they either sink to the bottom or attach to some sort of relatively still surface, like a plant leaf, a log, or a rock. The eggs hatch after about two weeks, and both the larvae and nymphs are both found in water, where they spend up to a year of their life as they mature, feeding primarily on detritus and algae, but occasionally they will eat other small aquatic insects. The following spring or summer, in the course of about 24 hours they will leave the water, molt into adults, fly about in a horde, mate, lay eggs in the water, and die. This sudden event often results in mass carpets of mayflies, which may need to be removed from your pond if it’s too much for your fish to consume.


2) Dragonfly Larvae

A dragonfly larva in a pond, which promotes ecosystem health
Photo by Charles J Sharp. Available under a Creative Commons Attribution-Share Alike 4.0 International license.

Like mayflies (and any other species on this list that includes “larvae” in the title), dragonflies begin their lives directly in the water as eggs that then hatch into larvae and develop further into nymphs. The adults don’t live in the water itself, but are always found near freshwater, typically slow-moving sources such as ponds near where they were initially born and will often land on the water’s surface to get a drink or hunt for small prey.

Interestingly, both the nymphs and the adults have almost 360 degree vision, which makes them excellent predators – they often feed on other insects, small mollusks and crustaceans, and occasionally very small fish fry (this shouldn’t be much of a concern for you, though, as they don’t prey on fish much and most aren’t large enough to be able to consume any fish at all). The nymphs stick toward the pond bottoms, where they are able to blend in, and abdominal gills enable them to obtain oxygen from the water (these gills are then, of course, lost once they enter the adult stage).


3) Stonefly Larvae

stoneflies can't tolerate pollution, and so are excellent indicators of healthy water quality
Photo by Bob Henricks. Available under a Creative Commons Attribution-Share Alike 3.0 Unported license.

Stoneflies are of the species that are intolerant of pollution, so having them in your pond is a good sign! In fact, they require between 8 and 10 parts per million (ppm) of dissolved oxygen. It’s possible for them to spend several years underwater as larvae or nymphs before they emerge as adults. Like mayflies, the adults have an incredibly short lifespan – about a day or two, just long enough to mate and lay eggs. The nymphs have gills in their armpits that enable them to stay submerged, and are typically less than an inch in size, making them palatable for many fish.


4) Water Strider

Water striders are common in ponds and feed on algae and other insects

Water striders, often nicknamed “skater bugs” because of the way that they appear to skate atop the water’s surface, can be found all around the world. They spend their entire lives in the water, both as nymphs and as adults. Their skin contains tiny specialized holes called spiracles that enable them to absorb oxygen directly into their bodies without lungs or gills. They look quite mosquito-like, but don’t bite or otherwise cause harm – they just skim about on the water’s surface, feeding on living and dead insects as well as algae. They make a tasty treat for just about any fish, but their long legs are hypersensitive and are able to pick up on slight vibrations, making them a bit of a challenge to catch.


5) Damselfly Larvae

Damselflies in ponds indicate healthy water quality
Photo by Charles J Sharp. Available under a Creative Commons Attribution-Share Alike 4.0 International license.

Like stoneflies, damselflies are also incredibly sensitive to pollution and thus are used to monitor water quality. They’ll spend their larval and nymph stage in the water, and their adult stage flying and living near the water. The adults look quite similar to dragonflies as they also have a double set of membranous wings, but while a dragonfly’s back wings are larger than its front wings, the wings of a damselfly are all approximately the same size. They often prey on other insects, and both nymphs and adults may be eaten by fish.


6) Water Bug

Water bugs are predatory, can grow very large, and are potentially harmful to fish in ponds

Of all the insects on this list, water bugs may be the ones that you want the least. They can grow quite large (some have reached upwards of half a foot in length, though 3 to 4 inches is more common for an adult that’s been around for a couple of years), and they’re predatory. They have armored bodies and a long, very strong “beak” that is able to easily pierce other insects as well as fish, and humans if we get too close or happen to step on them. It’s quite a painful bite, too, as they inject toxic saliva into their victim that can immobilize prey that’s on the smaller side, though they won’t hesitate to attack and consume things that are up to 8 times their own size.

Typically, they stay in the water where they’re fast swimmers despite their large size, but during mating season will fly from pond to pond in search of a mate and to lay eggs. They’re hardy and can fairly easily overwinter so long as the water doesn’t freeze solid, meaning that they’re able to live for many years, continuously growing. Younger, smaller water bugs can sometimes be eaten by some fish, but you should still try to remove them from your pond to prevent them from growing too large and potentially harming pond residents. They’re also pollution tolerant, and while this doesn’t necessarily mean that your water quality is poor if they’re around, it does warrant a quick water test.


7) Water Boatmen

Harmless water boatmen eat algae, detritus, and mosquito larvae in ponds
Photo by S. Rae. Available under a Creative Commons Attribution 2.0 Generic (CC BY 2.0) license.

Water boatmen are fairly small, usually about 5 to 15 millimeters long, and have four unique paddle-like back legs, two on either side of their body, and two normal front legs. These paddled legs help to propel them along beneath the water’s surface, where they spend their entire lives. From time to time they’ll come to the surface for air, then dive back down carrying a small air bubble with them that allows them to stay submerged for extended periods of time.

They are typically non-predatory, meaning that they mostly feed on algae and detritus, but they have been known to eat mosquito larvae. They may also feed on plants, injecting the plant with enzymes that help break it down so the water boatman can then simply suck it up. Unless you have a lot of water boatmen, they don’t usually cause excess damage to plants.


8) Caddisfly Larvae

caddisflies can only live in healthy, well oxygenated waters
Photo by Lorilei Thompson. Available under a Creative Commons Attribution-ShareAlike 3.0 License.

Caddisflies are another species that is often used to measure water quality, as they’re not able to survive in water that has below about 7 ppm of oxygen or is polluted. Caddisfly larvae and nymphs can be easily identified by turning over rocks – if you find case-like structures (about a centimeter or less in length) on the rocks that are composed of tiny bits of substrate, grains, plant matter, and pebbles, there’s very likely a tiny caddisfly larvae inside. They build these tubes both to protect themselves and to help catch food in slowly moving water.

Some caddisfly species will use plant matter and other available resources to build a small net-like structure to catch algae and small invertebrates that happen into the net, much like a spider’s web. They characteristically spend a year or less as larvae and nymphs before morphing into adults, where they, like mayflies, fly out of the water and mate within a day or two, lay eggs in the water, and die.


9) Backswimmer

Backswimmers eat other insects in ponds and promote a healthy ecosystem
Photo by S. Rae. Available under a Creative Commons Attribution 2.0 Generic (CC BY 2.0) license.

These little guys look quite similar to water boatmen and also possess the paddle-like hair covered legs, but they swim on their backs and this is the easiest way to distinguish the two species. They’re not considered harmful, and can overall be seen as a functioning and normal part of your pond’s ecosystem. Unlike water boatmen, backswimmers tend to be predatory and feed primarily on other insects, with the nymphs sometimes even being cannibalistic (though this may help keep the population at bay and encourage survival of the fittest).

 

37 thoughts on “List of Common Aquatic Pond Insects (Pictures & Identification)”

    • Hi Tyann,

      Apologies for the late reply!

      It could have been a damselfly nymph, as these can have wings and can be found out of water as well as in it, since they’re sort of in-between life stages as nymphs. It could also be a stonefly nymph or a mayfly nymph, as these all look rather similar! Damselfly nymphs will have three paddle-like tails, while the other two will have long, thin antennae-like tails. It’s possible that the larvae could have wandered out of water, though this would be unusual. Regardless of which it is, they’re all harmless! Simply move it/them outside near a water source and they’ll move on. They’re actually all three indicators of good water quality, so that means whatever nearby water source they came from is in good health!

      Reply
  1. Hi!
    Yesterday I saw a black larva which I thought was eating a brown fly/mossie type thing – but on reflection the black larva stopped moving, the blown fly skated on the water for a few seconds then flew off…what could that have been, please/ the larva was really black with a large head. All in all about 1cm long. Can’t recognise it from the pictures here.

    Also – all winter there have been brown muddy striations, seemingly made out of mud, perhaps containing larvae, looking like deposits (striped same direction )on the rocks in the pond. Have looked everywhere, have you any idea what they are? (Are they dangerous??)
    Thank you!

    Reply
    • Hi Annie!

      Thanks for reading and commenting!

      Did the black larva appear beetle-like, fly-like, crab/scorpion-like, centipede-like, etc.? There are many different types of macroinvertebrates, and the same species can look remarkably different depending on its life stage, and many species look the same as other species at different points in their life cycle. Any further descriptive clues that you can get will be immensely helpful!

      As for the mud deposits on your rocks, those are likely caddisfly larvae! They build tube-like nests for themselves on the bottoms of rocks with mud, sand, pebbles, twigs, and just about anything else small enough for them to use. It helps protect them from predators and water currents while they’re weak and developing. They’re not only harmless, caddisflies prefer healthy, non-polluted waters, so I’d say they’re a good sign for your pond! They also provide a good protein source for any fish that choose to eat them, and help control algae populations. As adults, they of course leave the pond and fly, providing food for birds, bats, and the like. Overall a good species to have around! If the tubes were there all winter, they may just be empty tubes from last year. Regardless, though, not at all a threat to your pond!

      Reply
  2. Hey This little critter is bugging me (lol) I found loads of them in a little pond in my garden. They looked like little twigs at first, but on closer inspection they are actually little insects inside individual mossy covered ‘shells’. The face looks almost wasp like, when it decided to come out, but I have no clue what they are. Can anyone help me? Thanks so much

    Reply
    • Hi Jay,

      Thanks for reading!

      Without a picture, it’s hard to know for certain. Caddisfly larva are known for making themselves little homes from mud, twigs, pebbles, and whatever they can find, so it could be that. Though they tend to look a bit more scorpion-like as opposed to wasp-like. It could also be a dragonfly or damselfly larva, as those do indeed look rather wasp-like and may crawl inside of something like a shell for shell-ter (ha, just adding to your pun!). Regardless of which of those three it is, they’re all considered indicators of a healthy ecosystem, so kudos to you!

      Reply
  3. Hi just been fishing in my pond, found a few tadpoles, and a newt tadpole and also some small thin creatures about 6 to 8 millimetres long like small worms. They appeared to have legs, or that may be my eyes. any ideas.

    Reply
    • Hi Lynn,

      Can you provide any other details? It could be a number of things – midge larvae, caddisfly larvae, or something else if it didn’t actually have legs. Where was it located – approximate depth, was it hiding under or near something like a rock or log, was it in the open, etc.? Could you also tell what color it was, by any chance?

      Reply
  4. Hi, while tidying up some pond oxygenator I noticed quite a few small creatures living on them. After lots of googling I haven’t seen anything that remotely looks like them, so wondered if you have any thoughts? They’re too small to take a photo unfortunately. About 6mm long, 1-2mm at its widest, pale grey/transparentish, smooth, sleek shape going to a tapered end. Out of water they flap around a bit like a fish. No obvious eyes, no stripes or segments, and no protrusions (legs, antennae, fins). They are quite flat, and the head is a little bulbous, a bit like a tadpole (but you only see this side-on, unlike a tadpole where you can see the head from above). Thanks in advance!

    Reply
  5. I live in Northern California. I have two koi ponds connected by a small “river.” There are little black beetle or snail-like critters living on rocks underwater in the slow moving water of the river. There are none in the ponds. They are mostly shiny black but some have a bit of brown. They are about 2-8 mm. I see hints of legs but nothing really clear. I see some antennae. They appear to have a pointed end some with a small white dot on the end. They move around slowly. I would send pics but I don’t see a way to do this.
    Any help with identifying these guys would be appreciated.

    Reply
  6. Just had water lettuce delivered and we always checks first before adding to pond as we have over 30 koi! This ugly looking earwig looking bug is swimming about. It swims with antenna head shaped like a v.. first and can wiggle about. Color is black Please help. and I’ve noticed many are asking how to post a picture and myself included!

    Reply
    • Hi Paulette,

      What part of the world do you live in? Species can vary significantly from region to region. From your description, however, I believe that it may be alderfly larvae (this is actually a beneficial species that shouldn’t harm anything, but rather provide food for fish and birds). If you’d like to take a look, I’ve attached a short and sweet guide to some of the more common macroinvertebrates found in the U.S.: https://dep.wv.gov/WWE/getinvolved/sos/Documents/Benthic/WVSOSAdvanced_MacroGuide.pdf

      In terms of pictures, I’ll pass along your feedback! As you can imagine, Pond Informer has received some unsavory comment submissions over time, which we filter out, and adding in a function to allow for the posting of pictures poses some extra threat of that. I’ll pass it along, though, and see what we can do 🙂

      Reply
    • Hi Paulette,

      Apologies for the late reply!

      We don’t allow pictures to be posted on the site for security reasons, but I’ll link you to a site we use that’s secure and private: Postimage.org — free image hosting / image upload
      Provides free image upload and hosting integration for forums. Free picture hosting and photo sharing for websites and blogs.

      Reply
  7. I found millions of tiny black worm-like things in my pond waterfall. What are they and will they hurt my Koi and goldfish?
    I have pictures but not sure how to post to this.

    Reply
    • Hi J. Lucas,

      Sounds like they might be black fly larvae or midge larvae. The adult flies will lay their eggs in the pond, and in the spring these develop into a great many larval worms. They should be gone within a few weeks, and won’t hurt your fish!

      Reply
    • Hi J. Lucas,

      We don’t allow pictures to be posted on the site for security reasons, but I’ll link you to a site we use that’s secure and private: Postimage.org — free image hosting / image upload
      Provides free image upload and hosting integration for forums. Free picture hosting and photo sharing for websites and blogs.

      Reply
  8. Hi,
    In the dregs of the bucket in which I was soaking my worm castings came these larvae (?) about an inch long, whitish, with a tail or flagelate device on one end. Seemed happy to be swimming around. Any ideas? I am in Southern California.
    Thanks very much.

    Reply
  9. Hi I have a 1 cm bug in my pond body in 2segments red, tail white with black dots live in UK . Any ideas? Have a photo not sure how to upload thanks

    Reply
    • Hi Julie,

      It’s a bit hard to tell without seeing it (we don’t currently have a photo uploading feature in place), but my guess would be some sort of fly larvae. I’m afraid I’m most familiar with US species, as that’s where I’m from, but after some digging I’ve found a resource that may prove helpful to you! It’s a guide to macroinvertebrates worldwide, and while it doesn’t have all species, it does have the most common and moderately common ones, so I’m hoping that it will be able to better guide you to an answer than I can. Just click on any species group and it’ll take you to a more detailed page! Hope that this helps.

      https://www.macroinvertebrates.org/

      Reply
      • hi, i seem to have alot of larvae in pond , they look like tadpoles but with arms ,theres little oxygen flow , is it okay to still swim in it as i been ? thank you

        Reply
        • Hi Leticia,

          It’s hard to know for certain without personally seeing them, but those sound like salamander larvae to me! Those are perfectly safe for you to swim with, but do try not to touch them as their skin is incredibly sensitive and will soak up anything that’s on yours (such as lotions, oils, perfumes, etc.).

          Reply
  10. Hi there
    I recently purchased some water starwort however it’s branches have been breaking off, just found this beetle on it and wondered if it could be the culprit? Or any other suggestions would be greatly appreciated!
    Just seen there’s nowhere to upload a photo, do you have an email address I could send it to?

    Reply
    • Hi Angela,

      We don’t allow pictures to be posted on the site for security reasons, but I’ll link you to a different site we use for images that’s secure and private: Postimage.org — free image hosting / image upload
      Provides free image upload and hosting integration for forums. Free picture hosting and photo sharing for websites and blogs.

      If you’d like to upload your pictures there, I can take a look and let you know what I think it could be!

      Reply
  11. Hi there
    I recently purchased some water starwort however it’s branches have been breaking off, just found this dark red beetle on it and wondered if it could be the culprit? Or any other suggestions would be greatly appreciated!
    Just seen there’s nowhere to upload a photo, do you have an email address I could send it to?

    Reply
  12. Hi,
    I found tiny black creatures in my garden water feature, they are about 5-6mm in length, swim quite fast, not sure if they are tadpoles as found a frog about 2 years ago on a main road, I put him in the garden as would have been killed on the busy road. Not sure if these are fly larva or from the frog.

    Reply
    • Hi Geraldine,

      Based on that description, it could be quite a number of things. If you don’t mind, could you upload a picture? We don’t allow pictures to be posted on the site for security reasons, but I’ll link you to a site we use that’s secure and private: Postimage.org — free image hosting / image upload
      Provides free image upload and hosting integration for forums. Free picture hosting and photo sharing for websites and blogs.

      Reply
  13. Hi
    I recently noticed lots of small (about 2mm) long bugs, which are living in the puddles at then centre of water lily leaves. They appear to have black and silver/grey mottled backs.
    I have a photo but not sure how to share this with you to help identify them.

    Reply
    • Hi Mark,

      We don’t allow pictures to be posted on the site for security reasons, but I’ll link you to a different site we use for images that’s secure and private: Postimage.org — free image hosting / image upload
      Provides free image upload and hosting integration for forums. Free picture hosting and photo sharing for websites and blogs.

      If you’d like to upload your pictures there, I can take a look and let you know what I think it could be! After you upload the image(s), you’ll have to also leave a comment here with a link to the image you just uploaded so that I can find it. Then I’ll take a gander and comment back here with a response! I know it might be a bit confusing and complicated – we’re looking into potential alternatives for image uploading in the future, but for now this is the safest option.

      Reply
    • Hi Mark,

      Thanks for getting back to me! I’ll be honest, I’m a bit stumped on this one. After quite a lot of digging, the closest thing I can come up with is possibly lily aphids. There are many different species, so their appearance can vary – the image is a bit blurry, but I think they match the size, body shape, and color description that you gave in your earlier comment. Do they seem to swim about, or do any damage to the water lilies? If the lilies that these bugs are found on are becoming damaged (yellowing or curling leaves, holes in leaves, stunted growth), then I’m confident that what you have are lily aphids.

      Reply
  14. We found a group of very very small insects the size of a needle point floating on the waters surface. The we’re moving around and are to small to identify.
    Any ideas?

    Reply
    • Hi Ralph,

      Is there any chance that you can take a picture of them? Preferably as close to and focused on one or two of the insects as possible so I can see as much detail as possible. We don’t allow pictures to be posted on the site for security reasons, but I’ll link you to a different site we use for images that’s secure and private: Postimage.org — free image hosting / image upload
      Provides free image upload and hosting integration for forums. Free picture hosting and photo sharing for websites and blogs.

      If you’d like to upload your pictures there, I can take a look and let you know what I think it could be! After you upload the image(s), you’ll have to also leave a comment here with a link to the image you just uploaded so that I can find it. Then I’ll take a gander and comment back here with a response! I know it might be a bit confusing and complicated – we’re looking into potential alternatives for image uploading in the future, but for now this is the safest option.

      Reply
  15. We have a small pond with a liner. We have always had Daphnia but this year there is something new. It’s several times larger than Daphnia, whitish in color and seem to be round. They are in all layers of the water. Any idea what they are?

    Reply
    • Hi Terri,

      Daphnia can range in size (some may be hardly visible, while others can be close to a centimeter in size), and their color is dependent on their diet. Daphnia that feed predominantly on bacteria tend to be white. If they look like Daphnia in everything but size and color, I would say that these are still Daphnia, just a different variety – there are over 200 species of them!

      If they don’t look like the Daphnia at all, though, would you mind uploading a photo? I’ll be better able to help you out that way!

      We don’t allow pictures to be posted on the site for security reasons, but I’ll link you to a different site we use for images that’s secure and private: Postimage.org — free image hosting / image upload.

      If you’d like to upload your pictures there, I can take a look and let you know what I think it could be! After you upload the image(s), you’ll have to also leave a comment here with a link to the image you just uploaded so that I can find it. Then I’ll take a gander and comment back here with a response! I know it might be a bit confusing and complicated – we’re looking into potential alternatives for image uploading in the future, but for now this is the safest option.

      Reply

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.