Also found in: Dictionary, Wikipedia.
an invertebrate animal of the order of isopod crustaceans. The body is 12-20 mm long. Found almost all over Europe, asellus aquaticus inhabits the under-water vegetation of lakes, rivers, and ponds. It moves along the bottom on six pairs of legs and feeds on the remains of dead animals and plants. Asellus aquaticus breathes through lamellar gills on the ventral side of the body. The young are hatched by the female in a brood pouch located at the base of the thoracic legs. Asellus aquaticus serves as food for fish. Sometimes the animals reproduce in large numbers (more than 7,000 individuals per sq m of bottom area) in stagnant bodies of water.