The aquatic or web-footed tenrec Limnogale mergulus is a semi-aquatic lipotyphlan known only from stream habitats of eastern Madagascar. It is a small tenrec, and the only one that lives in the water. The hind feet are webbed, and the tail flattened (to aid swimming). The pelage is dense and soft (no spines), the upperparts and head being brownish (with red and black guard hairs poking through).
The diet of Limnogale consists mainly of larval and adult aquatic insects, larval anurans and crayfishes. It is strictly nocturnal and remains in streamside burrows during daylight hours. It sleeps in burrows beside a stream. Breeding takes place between December and January. Litter size is around 3.