How do shrimp and lobsters swim backward rapidly?

Shrimp and lobsters, which are crustaceans belonging to the phylum Arthropoda, achieve rapid backward movement through a specialized escape response known as a "tail-flip."12

This sudden propulsion is generated by the animal's tail fan, which consists of paired uropods and the telson. When threatened, the lobster or shrimp performs a forceful flexure of its muscular abdomen and tail, which pushes the animal backward through the water. This explosive movement serves as an effective avoidance behavior, allowing these invertebrates to quickly escape potential predators.123