Alpheidae

Alpheidae, commonly known as pistol shrimps or snapping shrimps, is a diverse family of caridean shrimp found in oceans worldwide, with a strong presence in tropical and subtropical regions. Members range from small to moderately large and are characterized by asymmetrical claws, most notably an oversized major cheliped used to deliver a powerful snap.

The distinctive snap is produced when the enlarged claw closes rapidly, generating a high-velocity water jet that creates cavitation. The collapse of the cavitation bubble emits a sharp sound and a brief shockwave, which can stun prey or deter predators. In many species, this snapping behavior is linked to living in or near a burrow or shelter.

Many Alpheidae form mutualistic relationships with gobies (Gobiidae). The shrimp digs and maintains a shared burrow, while the goby acts as a lookout and signals danger, often retreating into the shelter at a threat. Some species in the genus Synalpheus exhibit eusocial colonies with a queen and cooperative brood care, a rare life history among crustaceans.

Habitat varies from coral reefs and rocky crevices to sandy or muddy substrates and seagrass beds. Most Alpheidae are omnivorous or carnivorous, feeding on small invertebrates, detritus, and sediment, often using their sensitive appendages to sample the environment.

Taxonomically, Alpheidae belongs to the infraorder Caridea and includes numerous genera such as Alpheus and Synalpheus. The group is popular in the aquarium trade, where pistol shrimps are valued for their behavior and audible snap, though their sometimes aggressive tendencies and specific tank requirements warrant careful husbandry.