Invertebrates
Water Louse
Asellus aquaticus · also called hog louse
Among rotting leaves on the bottom of a village pond, a water louse crawls slowly, a flat grey-brown relative of the woodlouse that has taken to the water.
Overview
The water louse, Asellus aquaticus, is an abundant isopod of ponds, lakes, canals, and slow rivers across Europe and northern Asia. Its flattened body, detritus-eating habits, and tolerance of poor water make it one of the commonest animals in the muddy corners of freshwater.
A recycler of the pond
By eating rotting leaves and dead matter, the water louse helps to turn waste into food for fish and other pond life.
Status
Not Evaluated, but abundant.
Water Louse: common questions
Is a water louse related to a woodlouse?
Yes, it is an aquatic isopod, related to the woodlouse, and crawls over mud, stones, and weed rather than swimming.
What does a water louse eat?
It eats rotting leaves, algae, and dead plant and animal matter, and is an important recycler in ponds and streams.
Does it live in polluted water?
It can live in water that is rich in nutrients or low in oxygen, where many other invertebrates cannot.
Where is the water louse found?
It lives in ponds, lakes, canals, and slow rivers across Europe and northern Asia.