Water louse
The water louse looks like a woodlouse that moved into the pond. It is a small grey-brown creature with long feelers that crawls around on stones under the water. It is a little cousin of crabs and shrimps.

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Fun facts
Its longer pair of feelers can be as long as its whole body.
Each of its little black eyes is made of only three tiny parts.
The mother carries her eggs in a pouch under her body.
Scientists look at which water animals live in a pond to check how clean the water is, and the water louse is one of them.
Some people keep it in aquariums as a little tank cleaner.
Most asked questions about Water louse
?Is a water louse an insect?
No. It is a crustacean, related to woodlice, crabs and shrimps. It has 14 legs, not 6.
?What does a water louse eat?
Dead leaves, algae and fungi on the bottom of the water.
?Is the water louse harmful?
No, it is completely harmless and helps clean ponds.
For bug experts
- Scientific name
- Asellus aquaticus
- Named by
- Linnaeus, 1758
- Group
- Woodlice
- Family
- Asellidae
- Classification
- Malacostraca > Isopoda > Asellidae
- Lives on
- Europe
- Also known as
- Pond slater, Aquatic sowbug, Water hoglouse, Cress bug
Where the facts come from
- Asellus aquaticus (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
- Picture by Peter Pfeiffer. CC BY-SA 4.0, Wikimedia Commons. The round sticker of this bug is cut from the same picture.
If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at [email protected] and we will fix it.