I have had a swimming pool (which is salt) for few months. 2 weeks ago I saw this:

close up of animal

I made a quick gif of a video:

enter image description here

Today, I found 4 more of this animal:

four more similar animals

All of them that are living I found in the water. I saw one beside, but it was dead.

I'm currently in France (in the middle). Around the swimming pool there is nothing except grass for 5m. Else it's my house, a hedge or just the grass continuing.

What is it? Is that dangerous/bad news that I have some of them?

  • $\begingroup$ Note* Saltwater won't do them a lot of good in the long-term as they're adapted to freshwater. $\endgroup$ Commented Sep 23, 2021 at 15:52
  • $\begingroup$ That's a good point, I don't really want them in my swimming pool ... $\endgroup$
    – Elikill58
    Commented Sep 23, 2021 at 15:58
  • 1
    $\begingroup$ Welcome to Biology.SE. Species-identification questions should use that tag. Amphibian is used for a group of vertebrates — these are insects so I replaced that tag with entomology. Please edit in an approximate size for your new "friends" as this may help with the identification. ——— Also note that whether this is "bad" is a matter of opinion, which is not appropriate for this site. Based on the suggested id (which seems correct to me) you can do some research and decide for yourself if this how you feel about their presence! $\endgroup$
    – tyersome
    Commented Sep 23, 2021 at 18:59
  • $\begingroup$ Thanks ! Yes, I search for the species-identification tag but i didn't find it. Thanks for edit. Yes, I say something opinion-based, but it's tolerated in comments ? $\endgroup$
    – Elikill58
    Commented Sep 23, 2021 at 19:25

1 Answer 1


Corixidae (Water-boatmen).

Aquatic insect comprising 6 subfamilies and 55 genera. (The Wikipedia page's right-hand panel contradicts the detail below that).

Size 2 - 15 mm long (0.1 - 0.6 inches), six legs, the front pair are hairy and shaped like oars. Feeding on aquatic plants and algae they range worldwide except Antarctica.

If I couldn't guess from the picture which of the 55 genera it might be as so many are wide-ranging and have similar morphology.

Edit: in response to bob1's comment, the related family notonectidae (backswimmer) deserves a mention.

Being of the same order as the corixidae above (the neomorpha), the backswimmer is distinguished by ... swimming on it's back. They're slightly bigger on the whole than their cousins and although primarily aquatic are able to migrate through flight. They can inflict a painful bite and are able to pierce with their proboscis - which they use to great effect in hunting tadpoles and small fish.

  • $\begingroup$ Thanks, yes it's seems to correspond ! Do you know if it's dangerous ? It seems no but idk $\endgroup$
    – Elikill58
    Commented Sep 23, 2021 at 15:55
  • 1
    $\begingroup$ @Elikill58 they are not dangerous but some of them can bite you,it gives a stinging sensation but it only last a very short time. $\endgroup$ Commented Sep 23, 2021 at 16:00
  • $\begingroup$ Thanks that's perfect ! :) $\endgroup$
    – Elikill58
    Commented Sep 23, 2021 at 16:01
  • $\begingroup$ Good answer. You should also include the Notonectidae (back swimmers) which are very similar, and the ones that bite as they are carnivorous. The Corixidae are mostly herbivorous I think. $\endgroup$
    – bob1
    Commented Sep 23, 2021 at 22:27
  • $\begingroup$ @bob1 Sure thing, I can't really tell from the picture which way up the thing is. Will edit. $\endgroup$ Commented Sep 23, 2021 at 23:38

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