Bump-head Mola

Mola alexandrini has a relatively small mouth, and its teeth are fused into a parrot-like beak. It can reach up to 3.3 m (11 ft) in length and 2,700 kilograms (6,000 lb) in mass, making it the heaviest bony fish. Their bodies are flat and round, with large fins that they swish back and forth to propel themselves with as they swim horizontally. Their skin has rough denticles and a leathery texture, with brown and gray coloring with pale blotches; at death, their scales turn white. The body has a thick white subcutaneous gelatinous layer that is smooth to the touch, with a laterally compressed body covered in small rectangular scales. All mola species have no caudal bones, ribs, or pelvic fins, and have fused vertebrae, leaving only their median fins to propel themselves. Mola alexandrini can be distinguished from Mola mola by its smaller number of ossicles and lack of a vertical band of denticles at its base. In Mola, the lower jaws are intact while the upper jaws are slightly forked. On the head, the lateral lines have small, white, rounded otoconia. On the sides are small gill openings covered by a soft gill membrane and gill rakers, which are covered under a subcutaneous gelatinous layer. All fins are spineless and triangular. …

Mola alexandrini has been found all over the globe and is widely distributed throughout the world's oceans, except for the polar regions. These species have been collected from waters off Japan, Taiwan, the Galapagos Islands, New Zealand, Australia, Turkey, Oman, and Spain. It can be found in the southwest Pacific, especially around Australia and New Zealand, and the southeast Pacific around Chile. Its range also extends to the southeast Atlantic near South Africa. During seasonal changes in climate on the Pacific side of Japan, M. alexandrini moves northwards in the summer and southwards in the winter. Seasonal migration is driven by temperature differences and productive frontal areas.

Sunfish spawn in the outer circulation of the temperate Atlantic and Pacific Oceans, as well as in the Mediterranean Sea. The optimal time for sunfish to spawn in the wild is not known, but research has shown that spawning in fall or winter, especially during the month of September, results in bigger fish. Fertilization occurs when sperm and eggs are shed in the water. Being that sunfish are so large, a single adult female can produce 300 million eggs. Unfertilized eggs were measured at 0.42-0.45 mm in diameter.