Ageing colourfully. This guy! — 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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Green moon wrasse, Norfolk Island, 17 July 2024

As is often the case while I’m out on my swim, last week this guy was circling me, right in my face, peering at me as he swam around and around. He’s the alpha male in the Emily Bay and channel area of Norfolk Island’s reef. The boss – a green moon wrasse, Thalassoma lutescens.

In the oblique afternoon light I could see he was looking a little scarred and care-worn. Like an old war horse with a few battle scars.

Which got me wondering. How long has he been swimming beside me? When did I first capture him on camera?

In a blog post back in September 2021, I remarked, ‘The green moon wrasse were very active and inquisitive this week. One, in particular, followed me for a good half an hour as I made my way around the reef off the Salt House.’

That ‘one’ was this guy.

I tend to take him for granted because he is always around, in my face, posing for photos. I apologise for anthropomorphising here, but he’s inquisitive, fearless, and oozes chutzpah. He’s like a pet puppy.

I was rather emotional after seeing him looking visibly older, but it spurred me on to see when he first appeared in my life. I pored over my green moon wrasse folder of photos (and there are quite a few in there), checking all the images out for matching markings on each side of their faces. I ended up with quite a few that are definitely him, and quite a few that are ‘maybe’s. Below are the definites.

The first definite photo is in November 2020, at which stage he was a young adult, probably having recently transitioned from female to male. By that November the blue band around his middle, only sported by terminal males, had intensified in colour.

Since then he’s gained a few dents and scars, probably had lots of babies, and generally lived the best life a green moon wrasse can live.

Here’s his story in photos.

(Cont’d below)

Left side

28 November 2020

4 September 2021

21 November 2022

5 December 2022

1 February 2023

8 March 2023

25 November 2023

2 July 2024

Right side

28 November 2020

7 May 2021

28 October 2021

26 November 2021

25 January 2023

14 May 2023

26 July 2023

2 July 2024

Green moon wrasse are said to live five to seven years in the wild, which means that our lovely old friend could well be classified as an elder. I am guessing that one day soonish he just won’t be there, but at least I can show my appreciation for his friendly, show-pony cheek with his own dedicated blog post.

You’ve gotta love him!

And if you want to see the different colours at different life stages for this species of fish, go to my fish page on this site, and scroll down to W for Wrasses.

May 28, 2026

A shrimp storm

While setting my research cams last week, I swam into what looked like an underwater snowstorm. It appeared to be the aftermath of a mass moulting event, with large numbers of tiny, translucent shrimp-like exoskeletons drifting together near the surface.

Kingston dredging: what happens when a reef does not fit the framework

This correspondence with DCCEEW is about more than one dredging proposal. It is about what happens when an ecologically distinctive place is assessed through standard tools that do not always make its most important values easy to see. I am publishing it here because that is something we need to be aware of, both on Norfolk Island and more broadly in Australia.

May 24, 2026

Kingston dredging: the project advances, the questions remain

Kingston dredging is edging closer, and the paper trail is growing. This post brings together earlier correspondence with the Department and the latest media release so readers can see what has been asked, what has been answered, and what still remains unclear about the project, its rationale, and the protections proposed for the reef.

May 17, 2026

The lime-green coral in Slaughter Bay – a 40-year paper trail

Green Mountain – the name I give this coral in my database – is a coral I’ve photographed for years as I swim past. Then I found its backstory in the Norfolk Island National Parks archives: a rough map, reused paper, a note in the margin – ‘still thriving’. That’s how baselines begin.

April 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?

March 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.

March 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.

March 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.

February 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.

February 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.