Update: 30 January 2018

On the morning of 30 January 2018, we released the Two Oceans Aquarium's resident ocean sunfish (Mola mola), which we had come to call Holy Moly, in the ocean off Robben Island.

Click here to read about the release.

Update: 27 December 2017

We removed the sunfish's temporary enclosure from the Predator Exhibit this morning and the sunfish is now swimming around the exhibit. We sent some divers in to help it around the tank and to closely monitor the sunfish's interactions with the other animals in the exhibit.

It is awesome to see such a gorgeous animal up close!

Photo by Ingrid Sinclair
Photo by Devon Bowen
Photo by Devon Bowen
Photo by Ingrid Sinclair
Photo by Ingrid Sinclair

On 21 December 2017 the Two Oceans Aquarium introduced an ocean sunfish (Mola mola) to its Predator Exhibit.

Photo by Ingrid Sinclair/Two Oceans Aquarium.
Photo by Ingrid Sinclair/Two Oceans Aquarium.

This sunfish had been spotted in the V&A Waterfront harbour for several days before the Aquarium team found it today – it has been a particularly busy time in the harbour, which we believe may be contributing to a degree of disorientation in the sunfish.

Photo by Devon Bowen/Two Oceans Aquarium.

The Aquarium is very happy to be able to put on display one of the ocean’s most mysterious animals. Most of our visitors will have never seen a sunfish, never mind actually knowing what it is! Those that are seen at sea are often mistaken for sharks because of the shape of their dorsal fin.

Photo by Cleeve Robertson.

The sunfish is being kept separate from the other inhabitants of the Predator Exhibit for the time being, so that we can feed and rehydrate it, and closely monitor its health and behaviour over the next few days. This will also give the other animals in the exhibit – ragged-tooth sharks, dusky kob, mullet and yellowbelly rockcod – a chance to get to know the newcomer.

The first feeding went very well. Photo by Devon Bowen/Two Oceans Aquarium.
Photo by Cleeve Robertson.

Our team constructed this temporary enclosure in record-time this morning in order to accommodate the sunfish inside the exhibit.

Photo by Cleeve Robertson.

The sunfish was covered in two types of parasites, which were painstakingly removed by hand, with tweezers, before the sunfish was gently lowered into the enclosure.

Says Curator Maryke Musson: “The parasite load on the sunfish was lower than expected – they’re usually covered in parasites – but we decided to bring it in to clean it off and keep an eye on it for a while.”

Parasites are removed by hand. Photo by Devon Bowen/Two Oceans Aquarium.

The sunfish also appears to have a big hole going through its chin. It looks like an old wound, possibly caused by a fishing hook, but we can’t be sure what caused it.

The sunfish has what looks like an old wound possibly caused by a fishing hook. Photo by Devon Bowen/Two Oceans Aquarium.

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.

From behind, a sunfish looks paper-thin. Photo by Ingrid Sinclair/Two Oceans Aquarium

The largest bony fish in the world

Ocean sunfish are the heaviest known bony fish in the world. 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.

The sunfish is gently lowered into the Predator Exhibit. Photo by Devon Bowen/Two Oceans Aquarium.
We use this crane to move heavy animals - this sunfish weighs 70kg! Photo by Devon Bowen/Two Oceans Aquarium.

Aquarist Simon Leigh, who helped move the sunfish into the exhibit, says he always wears gloves when working with sunfish: “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.

Our work with sunfish

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.

We also regularly help remove trapped sunfish from dry docks in the V&A Waterfront precinct. More recently, we sent one “flying”.

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.

One of a sunfish's most striking features is its big, wide eyes. Scientists believe that larger eyes could help sunfish identify prey over greater distances, and help them take advantage of lower light conditions at greater depths, so enabling sunfish to dive deeper to search for prey such as siphonophores (class of marine animals belonging to the phylum Cnidaria, which also includes jellies), according to Sunfish Research.

One of a sunfish's most striking features is its big, wide eyes. Photo by Devon Bowen/Two Oceans Aquarium.
Photo by Ingrid Sinclair/Two Oceans Aquarium
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