Ocean Sunfish, Mola mola (Linnaeus 1758)

Other Names: Common Mola, Giant Sunfish, Mola, Mola Ocean Sunfish, Short Sunfish

An Ocean Sunfish, Mola mola, at Punta Cannucce (depth ~45 m) Ventotene, Italy, August 2011. Source: Simone Carletti / Flickr. License: CC by Attribution-NonCommercial-NoDerivatives


This breathtaking oceanic giant is the world's heaviest bony fish. The Ocean Sunfish has a large blunt head, a small mouth with fused teeth forming a parrot-like beak, and tall slender dorsal and anal fins.

Instead of a caudal fin, Mola mola has a rudder-like structure called a clavus (meaning 'rudder' in Latin) – a deep, stiff lobe formed from extensions of the dorsal and anal fin rays. They also have a skeleton composed largely of cartilage, fewer vertebrae than other bony fishes, and lack pelvic fins, ribs, and a swim bladder.

The Ocean Sunfish grows to more than 3 metres in length, 4.2 metres in height, and can weigh more than 2.5 tonnes. Much of what is known about ocean sunfishes has come from stranded individuals.

Video of Ocean Sunfish having parasites removed by fishes and seagulls.

A huge Ocean Sunfish filmed off Portugal

Swimming with a gigantic Ocean Sunfish

Video of an Ocean Sunfish off Valparaiso, Chile

YouTube video of fishes and gulls removing parasites from Ocean Sunfishes.

Diving with Mola mola in Bali, Indonesia

Video of Mola mola in Bali, Indonesia being cleaned by Schooling Bannerfish (about 2:40 minutes into the video).

Video of Tierney Thys talking about her work tracking massive 10-foot long, 5,000-pound ocean sunfish, Mola mola around the globe.

Cite this page as:
Bray, D.J. 2020, Mola mola in Fishes of Australia, accessed 03 Dec 2023, https://fishesofaustralia.net.au/home/species/785

Ocean Sunfish, Mola mola (Linnaeus 1758)

More Info


Off Fraser Island, Queensland, around southern Australia to Mandurah, Western Australia, including Tasmania; also Christmas Island in the eastern Indian Ocean. Elsewhere the species is circumglobal in tropical and temperate seas.

Once thought to be a sluggish, sedentary species, Mola mola is actually an active swimmer, regularly diving to feed in depths below 200 m - and individuals have been recorded beyond 1000 m. 

To warm themselves up after spending time in very cold deep water, Ocean Sunfish spend much of their time in the top 200 m of the ocean. They are often seen basking at the surface, flapping their dorsal fins out of the water.


Dorsal-fin rays 15–18; Anal-fin rays 15–18; Clavus 12 rays, ~8-9 ossicles; Pectoral-fin rays 11-13.

Deep-bodied fishes, with high dorsal and anal fins, a reduction and fusion of caudal fin elements resulting in a loss of the caudal fin, a clavus or rudder-like structure, no swim bladder, no pelvic fins and a reduced, cartilaginous skeleton.The clavus is made up of fin rays and musculature from the dorsal and anal fins. The vertebral column is very reduced, and ribs are absent. Although the sunfish body is very rigid and rather inflexible, the large dorsal and anal fins are very powerful.
Body depth 70–75% SL; head length 35–39% SL; visible broad band of reduced denticles (smooth to touch) alongside base of clavus from dorsal fin to anal fin.

The clavus is supported by about 12 rays, of which 8–9 bear ossicles. The ossicles are widely separated and less broad than the spaces between them. A visible band of reduced denticles (smoother to the touch than surrounding skin) is present at the base of the clavus extending from dorsal fin to anal fin.


To 3.3 metres in length and 4.2 metres in height between the tips of the dorsal and anal fins.


Dull brown or greyish above and on upper portion of sides, paling to whitish below; sides sometimes with paler (occasionally yellow) spots.


Feeds mostly on soft gelatinous invertebrates, especially siphonophores in deeper mesopelagic waters. Ocean sunfish also consume jellyfishes, comb jellies, slaps, small crustaceans, squids, fishes and zooplankton.

Research using stable isotope analysis, has shown that groups of small ocean sunfish (less than 1 metre in length) feed on a broad range of pelagic organisms (Syväranta et al. 2012).

Once thought to be relatively inactive fishes that fed on pelagic gelatinous animals, research and sightings indicate that molas undertake deep-water forays to feed on colonial animals such as siphonophores.


Very little is known of the biology of ocean sunfishes. The sexes are separate and fertilisation is external. Individuals larger than 250 cm TL are female. Although some spawning areas have been identified and females may produce up to 300 million tiny pelagic eggs, Mola larvae are rarely collected.

Ocean sunfishes swim by synchronously flapping their dorsal and anal fins, using them like a pair of wings to glide through the water. This mode of swimming is thought to be very efficient, allowing ocean sunfishes to repeatedly dive to remarkable depths.


Although not a commercially important species, ocean sunfishes are frequently taken in extraordinary numbers as bycatch in gillnet, driftnet, longline and midwater trawl fisheries. Although not targeted, some fisheries catch more Mola mola that the target species. 

Molids are used as a food fish throughout Asia and the largest markets are in Japan and Taiwan. They are also used in the traditional medicine industry. The marketing and sale of fish and fishery products derived from ocean sunfishes is banned in the European Union.


• IUCN Red List: Vulnerable

The targeting or incidental bycatch of ocean sunfishes is largely unregulated by fisheries around the world. Molas may also be 'finned' in some parts of the world, and may be threatened by floating debris such as plastic bags.


Recent molecular work showed that there is high genetic divergence among Mola mola, indicating that there are two clades – one found exclusively in the southern hemisphere, and the other comprising individuals from both hemispheres.

Ocean Sunfish are host to at least 50 parasite species (Abe et al. 2012). Schools of Ocean Sunfish have been observed 'sun-baking' at the surface while gulls and albatrosses pick parasites from their huge bodies.

Similar Species


Mola is from the Latin mola meaning "millstone", in reference to the disc-like shape of the body.

Species Citation

Tetraodon mola Linnaeus, 1758, Systema Naturae per Regna tria Naturae. Tom.1 Holmiae: 334. Type locality: Mediterranean Sea. 


Bray, D.J. 2020


Atlas of Living Australia

Ocean Sunfish, Mola mola (Linnaeus 1758)


Abe, T., Sekiguchi, K., Onishi, H., Muramatsu, K. & Kamito, T. 2012. Observations on a school of ocean sunfish and evidence for a symbiotic cleaning association with albatrosses. Marine Biology 159: 1173–1176 http://link.springer.com/article/10.1007%2Fs00227-011-1873-6

Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research Vol. 1-3 1260 pp.

Bass, A.L., Dewar, H., Thys, T., Streelman, J.T. & Karl, S.A. 2005. Evolutionary divergence among lineages of the ocean sunfish family, Molidae (Tetraodontiformes). Marine Biology 148: 405–414. http://www.springerlink.com/content/t61703371ml681u6/

Bray, D.J. 2008. Family Molidae. pp. 858-861 in Gomon, M.F., Bray, D.J. & Kuiter, R.H. (eds). Fishes of Australia's Southern Coast. Sydney : Reed New Holland 928 pp.

Britz, R. & Johnson, G.D. 2005. Occipito-vertebral fusion in ocean sunfishes (Teleostei: Tetraodontiformes: Molidae) and its phylogenetic implications. Journal of Morphology 266: 74–79. https://doi.org/10.1002/jmor.10366

Dewar, H., Thys, T., Teo, S.L.H., Farwell, C., O'Sullivan, J., Tobayama, T., Soichi, M., Nakatsubo, T., Kondo, Y., Okada, Y., Lindsay, D.J., Hays, G.C., Walli, A., Weng, K., Streelman, J.T. & Karl, S.A. 2010. Satellite tracking the world's largest jelly predator, the ocean sunfish, Mola mola, in the Western Pacific. Journal of Experimental Marine Biology and Ecology 393(1-2): 32–42. https://doi.org/10.1016/j.jembe.2010.06.023

Fraser-Brunner, A. 1951. The ocean sunfishes (family Molidae). Bulletin of the British Museum (Natural History) Historical Series 1(6): 89-121 figs 1-18 See ref at BHL

Gill, T.N. 1897. The distinctive characters of the Molinae and Ranzaniinae. Science 156: 966–967

Hays, G., Farquhar, M., Luschi, P., Teo, S. & Thys, T. 2009. Vertical niche overlap by two ocean giants with similar diets: ocean sunfish and leatherback turtles. Journal of Experimental Marine Biology and Ecology 370 (1–2): 134–143.

Hobbs, J.-P.A., Ayling, A.M., Choat, J.H., Gilligan, J.J., McDonald, C.A., Neilson, J. & Newman, S.J. 2010. New records of marine fishes illustrate the biogeographic importance of Christmas Island, Indian Ocean. Zootaxa 2422: 63–68

Hobbs, J-P.A., Newman, S.J., Mitsopoulos, G.E.A., Travers, M.J., Skepper, C.L., Gilligan, J.J., Allen, G.R., Choat, H.J. & Ayling, A.M. 2014. Checklist and new records of Christmas Island fishes: the influence of isolation, biogeography and habitat availability on species abundance and community composition. Raffles Bulletin of Zoology Supplement 30: 184–202 https://lkcnhm.nus.edu.sg/rbz/supplement-no-30/

Hutchins, J.B. 2001. Molidae. pp. 3966-3968 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 6 pp. 3381-4218.

Katayama, E. & Matsuura, K. 2016. Fine structure of scales of ocean sunfishes (Actinopterygii, Tetraodontiformes, Molidae): another morphological character supporting phylogenetic relationships of the molid genera. Bulletin of the National Museum of Nature and Science (Ser. A) 42(2): 95-98.

Johnson, G.D. & Britz, R. 2005. Leis' conundrum: Homology of the clavus of the ocean sunfishes. 2. Ontogeny of the median fins and axial skeleton of Ranzania laevis (Teleostei, Tetraodontiformes, Molidae). Journal of Morphology 266(1): 11-21 https://doi.org/10.1002/jmor.10242

Liu, J., Zapfe, G., Shao, K.-T., Leis, J.L., Matsuura, K., Hardy, G., Liu, M., Robertson, R. & Tyler, J. 2015. Mola mola. (errata version published in 2016) The IUCN Red List of Threatened Species 2015: e.T190422A97667070. Downloaded on 14 December 2016.

Linnaeus, C. 1758. Systema Naturae per Regna tria Naturae, secundem Classes, Ordines, Genera, Species, cum Characteribus, Differentis, Synonymis, Locis. Tom.1 Editio decima, reformata. Holmiae : Laurentii Salvii 824 pp.

Matsuura, K. & Tyler, J.C. 1994. Triggerfishes and their allies. In Paxton, J.R. & W.N. Eschmeyer (eds) Encyclopedia of Fishes. Sydney: New South Wales University Press; San Diego: Academic Press, 240 pp.

Nakae, M. & Sasaki, K. 2009. Peripheral nervous system of the ocean sunfish Mola mola (Tetraodontiformes: Molidae). Ichthyological Research 53: 233–246. https://doi.org/10.1007/s10228-006-0339-1 

Nakamura, I., Goto, Y. & Sato, K. 2015. Ocean sunfish rewarm at the surface after deep excursions to forage for siphonophores. Journal of Animal Ecology 84(3): 590–603 https://doi.org/10.1111/1365-2656.12346

Nyegaard, M., Loneragan, N., Hall, S., Andrew, J., Sawai, E. & Nyegaard, M. 2018. Giant jelly eaters on the line: Species distribution and bycatch of three dominant sunfishes in the Southwest Pacific. Estuarine, Coastal and Shelf Science 207: 1-5 https://doi.org/10.1016/j.ecss.2018.03.017

Nyegaard, M. & Sawai, E. 2018. Species identification of sunfish specimens (Genera Mola and Masturus, Family Molidae) from Australian and New Zealand natural history museum collections and other local sources. Data in Brief 19: 2404-2415 https://doi.org/10.1016/j.dib.2018.07.015

Nyegaard, M., Sawai, E., Gemmell, N., Gillum, J., Loneragan, N.R., Yamanoue, Y., Stewart, A.L. 2017. Hiding in broad daylight: molecular and morphological data reveal a new ocean sunfish species (Tetraodontiformes: Molidae) that has eluded recognition. Zoological Journal of the Linnean Society 182(3): 631-658 https://doi.org/10.1093/zoolinnean/zlx040

Petersen, S. 2005. Initial bycatch assessment: South Africa's domestic longline fishery, 2000-2003. Domestic pelagic longline fishery: Bycatch Report 2000-2003. BirdLife South Africa, 45 pp.

Phillips, N.D., Harrod, C., Gates, A.R., Thys, T.M. & Houghton, J.D.R. 2015. Seeking the sun in deep, dark places: mesopelagic sightings of ocean sunfishes (Molidae). Journal of Fish Biology 87: 1118–1126. https://doi.org/10.1111/jfb.12769

Pope, E.C., G.C. Hays, T.M. Thys, T.K. Doyle, D.W. Sims, N. Queiroz, V.J. Hobson, L. Kubicek & J.D.R. Houghton. 2010. The biology and ecology of the ocean sunfish, Mola mola: a review of current knowledge and future research perspectives. Reviews in Fish Biology and Fisheries 20(4): 471-487. https://doi.org/10.1007/s11160-009-9155-9

Potter, I.F. & Howell, W.H. 2010. Vertical movement and behavior of the ocean sunfish, Mola mola, in the northwest Atlantic. Journal of Experimental Marine Biology and Ecology 396(2): 138-146.

Santini, F. & Tyler, J.C. 2002. Phylogeny of the ocean sunfishes (Molidae, Tetraodontiformes), a highly derived group of teleost fishes. Italian Journal of Zoology 69: 37-43. https://doi.org/10.1080/11250000209356436

Sawai, E., Yamanoue, Y., Nyegaard, M. & Sakai, Y. 2017. Redescription of the bump‑head sunfish Mola alexandrini (Ranzani 1839), senior synonym of Mola ramsayi (Giglioli 1883), with designation of a neotype for Mola mola (Linnaeus 1758) (Tetraodontiformes: Molidae). Ichthyological Research 65: 142–160. https://doi.org/10.1007/s10228-017-0603-6

Schmidt, J. 1921. New studies of sun-fishes made during the ‘‘Dana’’ Expedition, 1920. Nature 107: 76-79.

Sims, D.W., Queiroz, N., Doyle, T.K., Houghton, J.D.R. & Hays, G.C. 2009. Satellite tracking of the World's largest bony fish, the ocean sunfish (Mola mola L.) in the North East Atlantic. Journal of Experimental Marine Biology and Ecology 370(1–2): 127–133.

Syväranta, J., Harrod, C., Kubicek, L., Cappanera, V. & Houghton, J.D.R. 2012. Stable isotopes challenge the perception of ocean sunfish Mola mola as obligate jellyfish predators. Journal of Fish Biology 80: 225–231.

Watanabe, Y., Sato, K., 2008. Functional dorsoventral symmetry in relation to lift-based swimming in the ocean sunfish Mola mola. PLoS ONE 3, e3446. PDF Open access

Watson, W. 1996. Molidae, pp. 1439-1441. In Moser, H.G. (ed.) The Early Stages of Fishes in the California Current Region, CalCOFI Atlas No. 33. 

Yamanoue, Y., Miya, M., Matsuura, K., Katoh, M., Sakai, H. & Nishida, M. 2004. Mitochondrial genome and phylogeny of the ocean sunfishes (Tetraodontiformes: Molidae). Ichthyological Research 51: 269–273

Yoshita, Y., Yamanoue, Y., Sagara, K., Nishibori, M., Kuniyoshi, H., Umino, T.,  Sakai. Y., Hashimoto, H. & Gushima, K. 2009. Phylogenetic relationship of two Mola sunfishes (Tetraodontiformes: Molidae) occurring around the coast of Japan, with notes on their geographical distribution and morphological characteristics. Ichthyological Research 56: 232–244.

Quick Facts

CAAB Code:37470002

Conservation:IUCN Vulnerable

Habitat:Oceanodromous, pelagic-oceanic

Max Size:3.3 metres; 2.7 tonnes

Max weight:World's heaviest bony fish

Species Image Gallery

Species Maps

CAAB distribution map