Fish

Potato cod

Epinephelus tukula

A huge, blotched grouper that holds its patch of reef. Potato cod come and go on their own terms, and every sighting is a privilege, never a promise.

Least ConcernIn 6 Atlas countries

Least Concern (IUCN, assessed 2016, published 2018) means it is not close to being threatened. It is still vulnerable to spear fishing, and numbers at popular dive sites can fall.

Potato cod resting on sand under a coral overhang at Cod Hole, Ribbon Reefs, Great Barrier Reef — Photo: Richard Ling, Wikimedia Commons, CC BY-SA 2.0

Close view of a potato cod head with two small cleaner wrasse working near its mouth and eye, North Horn, Osprey Reef, Coral Sea — Photo: Richard Ling, Wikimedia Commons, CC BY-SA 2.0

Potato cod swimming over a reef at Aliwal Shoal, South Africa, with other reef fish nearby — Photo: Tom Heijnen, iNaturalist, CC BY

Potato cod close to the reef with its mouth slightly open, a diver photographing in the background, KwaZulu-Natal, South Africa — Photo: Chris Taklis, iNaturalist, CC BY

Photos show the species, not always the places on this page.

Length

Up to about 2 m (6.6 ft). Fish at Cod Hole are often described as 1.5 to 2 m (5 to 6.6 ft).

Weight

Up to about 110 kg (240 lb). Reports for Cod Hole vary widely, so the weight of any one fish is uncertain.

Next to a person

A large adult can be longer than a person is tall and as heavy as one or two adults.

What it eats

An ambush predator that swallows its prey whole: small rays, crabs, fish, squid, octopus and spiny lobsters.

Around people

Calm, look only

How it lives

Juveniles live in shallow tide pools, and adults live on coral reef channels and around seamounts with strong currents, from about 10 to 150 m (FishBase gives down to 400 m). Fish mature at about 90 to 99 cm and roughly 12 years, and the generation time is about 8.5 years. They are solitary and territorial, and described as aggressive towards intruders. Captive fish have changed sex, but spawning aggregations are unconfirmed for this species.

Where it goes

A solitary fish with a small home range, so an individual tends to stay around the same reef or cave. At Cod Hole on Ribbon Reef 10, the Great Barrier Reef, fish have been used to divers since the 1970s. They are described as not tame in any real sense.

We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.

Populations

Least Concern (IUCN, assessed 2016, published 2018). It is protected in South Africa and Australia, but it is exploited by local fisheries and is vulnerable to spear fishing. FishBase rates its fishing vulnerability as high (66 of 100) with low resilience. At Cod Hole, the average number seen per dive almost halved between 1992 and 1998 as visits grew. No global population count was found.

Meet it respectfully

Look and photograph only. Never feed, touch or bait it: feeding at Cod Hole made fish bold, and reef managers still debate it. It is territorial and can be aggressive towards intruders, so give it space and never corner it or reach for it. Stay off the coral, and follow your operator's briefing and local rules. No one can promise a sighting.

Fun fact

Tap the bulb to light it up.

Sources for this page

Facts checked 5 October 2026. Photos: Unsplash licence, or Creative Commons as shown on each photo.

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