One can deduce the possible behaviour of long extinct animals based on the behaviour of modern species that show a similar anatomy.

Modern flying fish belong to a different family to Cheirothrix lewisii, but in both groups the pectoral fin is extraordinarily well developed and the ventral lobe is the longest lobe of the tail fin. This suggests that these extinct fish probably also used their fins for high-speed, airborne gliding in order to escape predators.