Overview
The Sharptail Mola (Masturus lanceolatus) is one of the ocean’s most colossal and mysterious bony fishes. A close relative of the famous ocean sunfish (Mola mola), this deep-diving pelagic giant is instantly distinguished by a prominent, sword-like pointed projection protruding from the center of its rudder-like tail structure (clavus), cutting an imposing and prehistoric silhouette as it navigates both sunlit surface currents and pitch-black abyssal trenches.
Biology and Physical Characteristics
Possessing a laterally compressed, disc-shaped body that lacks a true caudal fin, Masturus lanceolatus relies on monumental dorsal and anal fins that wave synchronously from side to side like wings to propel its multi-ton mass. Its modified tail, or clavus, terminates in a sharp, elongated median lobe that differentiates it from all other molid species. Its skin is thick, rough, and rubbery, lacking typical fish scales and insulated by an extensive subcutaneous cartilaginous gelatinous layer up to six inches thick. Its small mouth contains teeth fused into a stout, beak-like cutting structure used to sever gelatinous zooplankton.
Behavior and Ecology
While historically assumed to be passive drifters that simply basked flat at the ocean surface, modern satellite tracking reveals that sharptail molas are vigorous, athletic divers. They regularly undertake vertical foraging excursions down to 2,000 feet (600 m) into icy, oxygen-depleted mesopelagic depths to feast upon deep-sea siphonophores and bioluminescent squids, repeatedly ascending to surface waters to ‘thermally recharge’ in warm sunlit surface layers.
Conservation and Human Impact
Classified as Data Deficient by the IUCN due to its vast pelagic offshore distribution and secretive deep-sea habits, the sharptail mola is frequently captured as unintended bycatch in commercial pelagic driftnets, longlines, and tuna purse seines. Furthermore, because molas consume large quantities of translucent pelagic siphonophores, they are intensely vulnerable to ingesting floating plastic debris that mimics jellyfish, leading to lethal gastrointestinal blockages.
Interesting Factoid
Despite growing to more than 11 feet in length and weighing upwards of two tons, a newborn sharptail mola larva hatches from an egg smaller than a grain of sand (less than 1.5 millimeters) and is covered in star-like defensive spikes!
Last updated: October 2026