Black Devil Snail (Faunus ater)

Faunus ater is associated with estuarine, brackish, and freshwater habitats in tropical parts of the Indo-Pacific. It often occurs where rivers and coastal waters meet.

Its elongated shell is commonly dark brown to nearly black, which inspired the English common name. The name is descriptive and does not mean the snail is dangerous like a venomous cone snail.

Look for a large, elongated, dark shell in a tropical estuary or freshwater-connected habitat. Its tall form separates it from rounded nerites and low-shelled limpets.

It can occur across a range from estuarine and brackish water to freshwater. Its ability to use these connected habitats is one of its defining ecological features.