The Physalia physalis species is characterized by a solitary gas-filled float, known as the pheumatophore, which is easily identifiable. Unlike numerous other siphonophores that utilize a cluster of swimming bells for buoyancy, Physalia physalis relies on this single float. Its contractile tentacles, when fully extended, can measure between 10 to 20 meters in length. The purple crest of the float is distinguished by a streak of pink running along it.