Banded, convict and spotted snake eels - know the difference

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.

This blog is rated in the Top 20 Coral Reef Blogs in the world.

The last day of winter, but here on the island spring is already with us. The bees are furiously busy with the clover in our paddock and the lavender hedge, while the tips of the frangipani trees are pushing out new leaves.

Glorious sunshine and winds from the southwest for a couple of days this week meant I was battling against it while swimming at the weekend!

A beautiful banded snake eel, Leiuranus semicinctus, popped into view on Saturday (top image). I haven’t seen any of these, apart from one dead one a few weeks ago, over winter, so it was wonderful to see this handsome fellow the other day.

I often get asked if these are sea snakes and if they are dangerous. They are in fact, as their name suggests, eels, and I find them to be very docile and will generally swim away or dive incredibly fast into the sand when approached too closely.

We have a few different snake eels: spotted, banded and convict. I’ve included photos of all three here so you can see the difference. It has been suggested to me that we may have a couple of different subspecies of these – which are, as yet, undescribed – because a couple look a little different. This isn’t something I know much about, but it would be exciting beyond belief if we did have some unique ones here.

Below are images of the three different types of snake eels found in Norfolk Island’s lagoons.

Ocellate snake eel - Myrichthys maculosus

Banded snake eel - Leiuranus semicinctus

Convict snake eel - Leiuranus versicolor

A convict snake eel, Norfolk Island

One thing I love to watch is the bluestreak cleaner wrasse, Labroides dimidiatus, hard at work. You often see fish queueing up for a once-over from this little guy. This morning it looked like they were all getting in early for a spring clean! I’ve included a few photos of this busy beaver cleaning some yellowstripe goatfish, Mulloidichthys flavolineatus (left) and a Coral Sea gregory, Stegastes gascoynei (right).

Bluestreak cleaner wrasse with goatfish

Bluestreak cleaner wrasse with a Coral Sea gregory

Jun 17, 2025

Poop power

Not all poop on a reef is bad poop. In fact some kinds of poop can be a reef’s most important invisible engine. Fish poop, bird poop – even poop that gets eaten again by other fish – all of it keeps the ecosystem ticking over in a way that’s nothing short of extraordinary.

Jun 13, 2025

Glimpses of recovery: what the reef could be if we let it

Day 6 of this photo series from Norfolk Island coincides with the final day of the UN Ocean Conference in Nice. After a week of documenting decline, today’s post offers a different view – what reef recovery can look like when conditions improve. Drought in 2024 gave the reef a break, and the results were unmistakable: healthier corals, lower disease, and more fish. This is what’s possible if we act.

Jun 12, 2025

Warning signs: quiet and unnoticed collapse of two coral colonies

Day 5 of my blog series for the UN Ocean Conference: two long-lived coral colonies in Norfolk’s lagoon died quietly from disease. No drama – just slow collapse and overgrowth by algae. A reminder that not all reef losses are loud, but they are happening.

Jun 11, 2025

Warning signs: what Norfolk Island’s reef is telling us

Day 4 of a week-long photo series from Norfolk Island, shared during the UN Ocean Conference in Nice. Today’s post spotlights a Hydnophora pilosa colony where white syndrome appeared suddenly and spread quickly, taking out around a quarter of the coral. In the months that followed, algae quietly filled the gap – a subtle but telling shift from coral to algae that’s happening across the reef.

Jun 10, 2025

Warning signs: coral disease takes hold

In Day 3 of this blog post series, published while leaders gather at the UN Ocean Conference in Nice, we see Norfolk Island’s coral reef lagoon quietly delivering a stark warning: recurrent land-based pollution, coral disease, and delayed decisions are dismantling this ecosystem in real time.

Jun 9, 2025

Warning signs: coral growth anomalies – the slow cancers of the reef

Day 2’s post coinciding with the UN Ocean Conference looks at coral growth anomalies – sometimes called coral ‘cancers’. These slow-moving diseases quietly weaken coral colonies, making them far more vulnerable to storm damage and algal takeover. On Norfolk Island’s reef, I’ve watched this exact process play out over several years. This is how chronic stress silently dismantles coral ecosystems.

Jun 8, 2025

Warning signs: shifting baselines on Norfolk Island’s reef

Today is World Ocean Day — a timely moment to launch my week-long blog series on Norfolk Island’s reef. Each day this week, I’ll be sharing photo essays that document the slow but steady pressures reshaping this fragile reef. Today: how shifting baselines make us blind to what we’ve already lost.

Apr 29, 2025

The Governance–Government Vacuum: Norfolk Island’s Forgotten Ecology

A personal reflection on Norfolk Island’s coral reef environment, political denial, and what John Wyndham’s The Kraken Wakes can still teach us about slow-moving disasters — and why this election matters more than ever.

Feb 20, 2025

Cute as buttons – Astrea curta

Astrea curta corals are ‘small, moderately plocoid [flattened], distinct, and almost circular’ . Normally grey-green in colour, you can see from the images here, ours are often beautiful rich gold, although they do vary. They have a neat growth habit and button-like corallites, which can grow in columns, spherically or flattened. Large colonies of these can form gorgeous undulating bumps.

Jan 26, 2025

From 'Watch' to 'Warning'

Last week, the chance of coral bleaching in Norfolk Island’s inshore lagoons was raised from ‘Watch’ to ‘Warning’ and will more than likely rise to Alert levels one and two in coming weeks. So why do I worry about water quality all the time when bleaching seems inevitable these days and so the reef is probably doomed anyway? Read on to find out.