No, it's not a parrotfish! — Norfolk Island's Reef

Out on A Swim

‘Out on a swim’ is a coral reef blog that tells the stories of the characters who live under the waves and what has caught my eye when ‘out on a swim’ in the lagoons of Norfolk Island. It is also a record of the difficulties Norfolk Island’s reef faces, like many others around the world, as a result of the poor water quality that has been allowed to flow onto it.

This page shows the most recent blog posts. For the complete catalogue, visit the ‘Out on a swim index’ page.

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I often get people excitedly telling me how they have seen a parrotfish. And it is quite possible that they have. But to be honest, the few parrotfish that we do have are rather dull when compared with their more flamboyant wrasse cousins and there are very few of them, both in numbers of parrotfish species and in the numbers you will see of each one. If I see a parrotfish, any parrotfish at all, it is rare. And when I do see them it is often just an individual or possibly a small family group. So it is more likely that the large brightly coloured fish they are telling me about is either a surge wrasse – Thalassoma purpureum, or a green moon wrasse – Thalassoma lutescens, both of which are plentiful in the lagoons.

Green moon wrasse - *Thalassoma lutescens*

I have observed five species of parrotfish inside the reef. You can find them all under P for parrotfish if you scroll down on my fish page on this website. Keep scrolling down to W for wrasse to see the amazing variety of these.

Parrotfish are a subspecies of the wrasse family. Like wrasses, they swim using their pectoral (side) fins, which can look a little like mini wings as they move through the water.

One of the features that sets them apart from wrasses is their toothy grin and fused teeth – about 1000 of them lined up in 15 rows – in a beak-like form, hence their name. They eat ‘microscopic filamentous bacteria that live on, and just a few millimeters underneath, the calcareous surface of the reef’, and to get at these they chow down on the hard coral skeletons. More teeth in their throat (plates known as a pharyngeal mill) grind the coral into a paste so they can extract the nutritious coral polyps and algae. What comes out the other end is beautiful white sand.

Wrasse, on the other hand, like to consume invertebrates, such as shrimps, crabs, sea urchins and gastropods. They have soft protractile lips to help them nibble.

Parrotfish are vital to the health of coral reefs. In places where they have been overfished, the ecosystem is not as productive. So perhaps it’s best to leave them where they are.

More information about parrotfish can be found in this fascinating article from the Smithsonian here: ‘Tough Teeth and Parrotfish Poop’, Ocean.

Bluebarred parrotfish - Scarus ghobban

Marbled parrotfish - Leptoscarus vaigiensis

Pacific Bullethead Parrotfish - Chlorurus spilurus

Palenose parrotfish - Scarus psittacus

Surf parrotfish - Scarus rivulatus

Fused front teeth of the bluebarred parrotfish

Apr 5, 2026

What Norfolk Island’s reef tells us about environmental blind spots

The Kingston dredging proposal on Norfolk Island raises a bigger question than dredging alone: how well do standard environmental assessment tools capture the real significance of a remote and unusual reef system like Norfolk Island’s?

Mar 30, 2026

Hammer coral time!

Hammer corals have unique tentacles that are large, fleshy, and tubular; these terminate in a ‘T’-shaped, hammer-head or anchor. Beneath all these softly waving tentacles is an extraordinary skeleton structure, which helps define them as a large polyp stony coral.

Mar 24, 2026

Norfolk Island’s fishes: drifters, residents and the ones still missing

Norfolk Island’s fish fauna reflects both connection and isolation. Some species may arrive from elsewhere as drifting larvae, some populations appear to persist locally, and some fishes known from islands on either side of Norfolk have still not been recorded here. This post looks at what old survey work, regional checklists and genetic studies suggest about that more complicated picture.

Mar 7, 2026

Alveopora or flowerpot coral – how to tell the difference

They look alike at first glance, but Alveopora and flowerpot corals are not the same. The easiest way to tell them apart is to count the tentacles.

Feb 27, 2026

Norfolk’s lagoonal reef – the 2025 report, in plain English

We now have the 2025 Norfolk Island reef health report, so I’m taking the opportunity to translate it into plain English here. Sadly, it’s more of the same story in Emily and Slaughter Bays – a reef that can cope with some stress, but is being asked to cope with too much, too often.

Feb 20, 2026

Halimeda’s night shift – why this reef algae changes colour

Halimeda is a calcareous green reef alga that forms new segments overnight, shifts from white to bright green by dawn, then pales again as calcification begins. A quick look at one of the reef’s smartest algae.

Jan 11, 2026

Reef real estate – a bubble-tip’s six-year stand-off

Reef space is finite, and nothing ‘shares’ it politely. This short photo essay follows one bubble-tip anemone on Norfolk Island’s lagoonal reef as it holds a crater surrounded by Montipora. The coral builds a rim; the anemone holds the centre. Six years apart, and the argument continues.

Dec 28, 2025

A year in review – 2025 on Norfolk Island's reef

Norfolk Island’s reef in 2025 – a year in review. From NOAA bleaching alerts and the UN Ocean Conference ‘Warning Signs’ series to post-drought coral recovery and a wet winter revealed in long-term rainfall records, this post captures the wins, losses, and shifting baselines beneath the lagoon. Includes reef photos, highlights from Reef Relief, and standout stories from 2025 – from coral health and disease to boxfish biomimicry, sea urchins, nudibranchs, and heat-stress signals in anemones.

Dec 15, 2025

Herbicides, heritage, and an inshore reef: what happens when land management meets lagoon health

Herbicide use near Emily, Slaughter and Cemetery Bays raises questions about inshore reef health, heritage land management, and environmental protection on Norfolk Island.

Dec 8, 2025

Signs of bleaching – 8 December 2025

I took these photographs this morning, Monday, 8 December 2025. A few warm days of settled weather, little cloud cover and low tides in the hottest part of the day have led to some early bleaching on our reef. Bleaching doesn’t always mean death for our corals, but it is concerning to have this so early in the summer season. Fingers crossed the conditions don’t last and the reef can recover.