The fish develop their truncated, bullet-like shape because the back fin, which is present at birth, never grows.

They are frequently seen basking in the sun near the surface and are often mistaken for sharks when their huge dorsal fins emerge above the water.

They are clumsy swimmers[citation needed] , waggling their large dorsal and anal fins to move, and steering with their clavus.

Their population is considered vulnerable,[4] as they frequently are snagged in drift gill nets and can suffocate on sea trash, like plastic bags (which resemble jellyfish, their main food source).

Kölreuter in 1766 published a fish name Mola but did not treat is as a Linnaean genus (i.e., not binominal), so the name is unavailable under the rules of the ICZN and cannot be used.