fish

Mar

2026

The World’s Largest Frogfish

Gerald McComack, CINHT

Pupuke Robati’s Frogfish caught 3km west of Rarotonga – Gerald McCormack

Frogfishes are a family of fishes that look like misshapen toads – hence the name frogfishes. They are usually less than 20cm long, with some species less than 5cm in total length. They are sedentary ambush-feeders. Unsuspecting prey are attracted to a small beacon on the frogfish’s snout only to discover they are falling into an enormous gaping mouth. Because their life-style is similar to the stonefish they look rather similar in appearance, although the beacon above the mouth is a giveaway. Frogfish do not have the defensive poisonous spines that make stonefish so feared.

On Easter Monday Pupuke Robati Jnr was trolling about 3km west of Rarotonga when he snagged a large grotesque fish, 2-3 metres below the surface. Having never seen such a thing before, he kept it and discussed it with Ian Bertram. They concluded that it was obviously a bottom living fish, and it was very strange that it was caught at the surface. Natural Heritage photographed the fish and emailed an image to Jack Randall at the Bishop Museum in Honolulu – a world authority on tropical fish. Jack identified it as Antennarius scriptissimus, noting that he had come across one in Tahiti a few years ago. Professor Ted Pietsch of Washington University (Seattle), the world authority on frogfish, confirmed the identification and provided additional information.

This species, which has no English name, is one of the most rare and least known frogfishes. It is known from six specimens from Reunion (west Indian Ocean), Philippines, Japan (2), North Island (New Zealand), and Tahiti. The largest specimen was about 35cm total length, which makes Pupuke’s fish at 50cm the world’s largest. Pupuke’s fish is not only the largest of its species, it is the largest of its family – it is the granddaddy of all frogfish! Unfortunately we are not in a position to give the species an English name but Pupuke’s Greater Frogfish would seem about right – and thanks to his curiosity the specimen is available to science. The specimen will be preserved at the University of Washington.

The addition of this new record to the Cook Islands Biodiversity Database brings the total number of marine fish (including sharks) to 633. Seven other new records have been added this year: Kevin Salisbury on Pukapuka added four, and Graham McDonald on Rarotonga and Manuae added three.

Author’s notes

First published CINEWS (April 2005 )

Feb

2026

Cook Islands’ Needlefishes

Gerald McCormack, CINHT

Illustration showing identifying features of the four needlefish species found in Cook Islands

The Cook Islands’ biodiversity database lists 650 species of marine bony-fishes. In looking at the distribution of fishes across the Pacific it is obvious that there must be at least another hundred to be recorded locally. The Trust is always interested in information on new and unusual records.

For the needlefish family the database lists four species: Keeled Needlefish (Miro Va‘a-roroa, Platybelone platyura), Houndfish or Crocodile Needlefish (‘Aku, Tylosurus crocodilus), Reef Needlefish (‘Aku, Strongylura incisa ) and the Flat Needlefish (Pāpā, Ablennes hians).

The Keel-jawed Needlefish has been recorded across the South Pacific, but not specifically in the Cook Islands. However, it is an off-shore species and therefore very unlikely to have been caught in Ngatangi‘ia harbour.

Many species of fish have distinctive features and are reasonably easily identified from photographs, but some require a more detailed analysis of specimens. In the illustration we show some of the more conspicuous features of the four species of needlefish positively identified in the Cook Islands.

Keeled Needlefish

Keeled Needlefish is the one commonly seen in the lagoon swimming with the half-beaks. They grow to about 40cm Total Length (TL). Their most distinctive feature is the long keels on each side of the tail-base. Local names include Miro Va‘a-roroa and Miromiro on Rarotonga, Akuaku and Kakukaku on the Makatea islands, and Miromiro on Aitutaki.

Crocodile Needlefish and Reef Needlefish

These two needlefish are very similar and share the name ‘Aku. The Crocodile Needlefish grows to about 130cm TL while the Reef Needlefish grows to about 100cm. Both have cylindrical bodies, lack distinctive colour markings, and have similar teeth as adults.

The most obvious separating feature is on the base of the tail – the Crocodile Needlefish has a conspicuous black keel on the sides while the Reef Needlefish has no keels. Another identifying feature is the Crocodile Needlefish’s tail which has a deep fork and a conspicuously long ventral lobe, while the Reef Needlefish has a blunt tail with the ventral lobe only slightly longer.

Both species are common near reefs and enter lagoons. The Crocodile Needlefish is known as Houndfish in America and Crocodile Longtom in Australia.

Flat Needlefish

The Flat Needlefish is easily recognised and is known as Pāpā on most islands, including Rarotonga. It has a deeper, flat-sided body with conspicuous black blotches on the sides of its body especially below the dorsal fin. It grows to about 130cm TL. It is an off-shore species and is not known to enter lagoons.

Injuries

The larger needlefishes can be attracted to the lights of night-fisherman and have been known to leave the water like a living javelin. There are a couple of known fatalities. In 1977 a boy was killed on Kaua‘i (Hawai‘i) and in 2007 a boy was killed in Vietnam.

What was the mystery fish (CINews 18/08) caught at Avana Wharf? Without seeing the tail it could be either a Crocodile Needlefish or a Reef Needlefish. Local fishermen, who distinguish between these two species, might notice features of the fish or its behaviour that makes it more likely to have been one species rather than the other.