Phronima is a small, deep sea hyperiid amphipod of the family Phronimidae. It is found throughout the world's oceans, except in polar regions. The body of Phronima is transparent. Females attack salps, using their mouth and claws to eat the animal and hollow out its gelatinous shell. She then enters the barrel and lays her eggs inside. She then propels the barrel through the water as the larvae develop, providing them with fresh food and water.