Aquatic sow bugs, water lice or water slaters

Collectors/gatherers/shredders/predators – aquatic sow bugs are omnivores and eat just about any organic material they come upon.

Aquatic sow bugs live at the bottoms of variety habitats. The most common they are in small streams and springs.

They crawl in crevices among rocks, in root masses, or tangles of aquatic vegetation.

Body length of adults ranges from 10 mm to 20 mm (without antennae).

Life cycle:
There is no separate larval stage. Young look like small adults and become sexually mature after growing and shedding their skin several times.


Crustaceans is a very large group of animals consisting of about 70 000 described species. Although the highest abundance and diversity is reached in marine environments, many crustaceans have colonized freshwater habitats.

Crustaceans have a tendency to fuse some body segments, in order to protect the body and adapt to specific conditions. Thorax and abdomen possess many specialized appendages for various purposes such as walking, swimming, gathering food, breathing, or reproduction.

The name crustaceans comes from their hard carapace, which is reinforced by the presence of calcium carbonate in its structure.

Even though aquatic sow bugs are freshwater crustaceans belonging to the order Isopoda, they lack characteristic carapace. Their segmented body is strongly flattened from top to bottom and divided into three groups: cephalothorax, thorax, and abdomen.

Cephalothorax consists of the head and the first thoracic segment. Next seven segments (each with a pair of legs) form the thorax. First pair of legs has enlarged ends, equipped with hinged claws for grasping food. Six remaining pairs of long legs end with a simple pointed claw.

Abdominal segments are fused into a short, shield-like plate. There are six pairs of appendages on the abdomen. Only the last pair of forked appendages protrudes the rear of the body. First five pairs (hidden from the top view) are plate-like structures responsible for breathing. Moreover, the movement of these plates brings oxygenated water to brood pouch, where eggs and hatched young develop.

Aquatic sow bugs (Asellus aquaticus):