We sometimes see Ocean Sunfish (or Mola Mola) in the waters off Gordon’s Bay and Cape Town. They’re not frequent visitors to our waters and smaller species have also been found washed up on our beaches after the strong south easterly winds.
Here are 20 things you might not have known about sunfish:
- The ocean sunfish is the heaviest bony fish species in the world.
- They can grow to over 4.2m vertically, 3m in length and weigh over 2,268 kg.
- There are three types of sunfish – the slender sunfish (Ranzania laevis); sharp-tailed sunfish (Masterus lanceolutus) and the southern ocean sunfish (Mola ramsayi).
- They are slow swimming and found in tropical and temperate waters of the Atlantic, Pacific, Mediterranean and Indian Oceans.
- They are flat, disc-shaped fish with a large dorsal fin, a ventral fin, two pectoral fins and a narrow scalloped tail.
- The tail of Ocean sunfish does not grow as the fish matures, instead it folds back on itself (this type of tail is called a clavus), giving the fish its “half fish” appearance.
- The word “mola” is Latin for “millstone” – which is what the flat, disc-shaped ocean sunfish looks like.
- They have a tiny mouth with beak like teeth made up of two fused teeth.
- Sunfish do not have scales but a tough, elastic skin.
- Sunfish can be covered with up to 40 different types of parasites (some of which have their own parasites too!).
- Sunfish are able to leap clear of the water.
- Ocean sunfish are related to puffer and porcupine fishes.
- Sunfish are often seen on the surface, lying on their sides – possibly to warm up after deep dives to colder water, to recover their stores of oxygen or to encourage cleaning of the skin of parasites by sea birds or fish.
- When they swim on the surface, their huge dorsal fins are often mistaken for those of sharks – until closer inspection!
- Sunfish can swim to depths of at least 500m and usually spend most of their time at depth during the day and closer to the surface at night.
- Ocean sunfish eat jellyfish, plankton, algae, molluscs, brittle stars and small fish.
- They reproduce by releasing eggs and sperm into the water. They have incredibly small eggs and produce many more than most fish.
- When sunfish larvae hatch, they have spikes and resemble pufferfish.
- Ocean sunfish are also sometimes called moonfish.
- Ocean sunfish are harmless to people.
Have you ever seen a sunfish? Look out for them on your next dive – they are really beautiful!