It was a cracker of a weekend for the rescue team at the Two Oceans Aquarium. After disentangling two seals in the V&A Waterfront on Sunday 27 December, our team was called out to the pier near Den Anker to help a disoriented ocean sunfish (Mola mola).
Says Curator Maryke Musson: “The sunfish was covered in parasites – as they usually are – so we decided to bring it in to clean it off and keep an eye on it for a while.”
The sunfish can now be seen in the I&J Predator Exhibit and we will keep it here to monitor its progress and health. We will keep a particularly close eye on how it is adapting to life with the other animals in the exhibit.
Whether it will stay with us for a day, a week or a month is not clear yet.
Many people have never seen sunfish – one visitor, on seeing the very first sunfish we had on display in the I&J Predator Exhibit, was convinced it was a robot! Those that are seen at sea are often mistaken for sharks because of the shape of their dorsal fin.
The Two Oceans Aquarium assists international researchers of sunfish with the collection of DNA samples when Aquarium staff members come across a sunfish in Cape Town waters. Click here to read more about our conservation work with sunfish.
When you come around to visit the sunfish, take note of its beautiful mottled skin patterns. You’ll also love its beaked mouth, like a parrot’s, and the way it looks paper-thin when viewed from directly in front or behind.
The largest bony fish in the world
“Ocean sunfish are the heaviest known bony fish in the world,” says Senior Aquarist Kevin Spiby. They are also known for being covered in skin parasites. To counter this, sunfish employ a number of tactics: cleaner wrasse and other reef fish often help out, and by basking on its side at the surface, sunfish allow seabirds to feed on parasites.
“We remove the parasites – which are like copepods – by hand, with tweezers,” says Kevin.
Aquarist Simon Leigh, who helped move the sunfish from the harbour to the holding facility at the Two Oceans Aquarium, says sunfish are his favourite fish to work with because you have to catch them by hand. “One thing to always remember though,” he says, “is to wear gloves. Sunfish have incredibly rough skin so it can chafe you, like sandpaper.”
The rough skin can be up to 7.3cm thick and is covered in denticles. Dermal denticles are “similar to scales, but are really modified teeth and are covered with a hard enamel,” according to About.com.
More interesting facts about these gentle giants
- Sunfish are so called because of their habit of drifting at the surface as if basking in the sun.
- Sunfish do not have tails as other fishes do – the caudal (tail) fin has been replaced by a rudder-like structure.
- The ocean sunfish has a rounded, wavy rudder.
- All sunfish have small mouths and the teeth are fused together in each jaw, forming a beak like that of a parrot. The beak is internal and hidden from view.
- Sunfish feed on jellies. It is remarkable that an animal that grows to such a large size subsists on a diet with very little nutritional value.
- Sunfish are not considered edible as they consist mainly of cartilage and gristle and their flesh is soft and insipid.
- They are the most fertile of all fishes, producing up to 300 million tiny eggs.
- The name “mola” is derived from the Latin word for millstone because of their similar shape.