Which snake has two small tentacles on its snout used to detect fish?

The snake with two small tentacles on its snout used to detect fish is the tentacled snake.

The tentacled snake (Erpeton tentaculatum) is an aquatic, rear-fanged snake native to Southeast Asia. Its paired snout appendages are unique among snakes and function as mechanosensory organs, helping it detect disturbances in murky water.

It spends essentially its entire life in freshwater or brackish habitats such as lakes, rice paddies, and slow-moving streams. Rather than chasing prey, it anchors itself with its tail and waits in a distinctive upside-down J-shaped posture. When a fish approaches, the snake can trigger an escape response and predict where the fish will move.

The species is sometimes confused with other water snakes, but its tentacles are the giveaway feature. It eats fish almost exclusively and has small venomous fangs deep in the rear of its mouth; its venom is specialized for prey and it is not considered dangerous to humans.