Most divers swim straight past their first ghost pipefish. It looks like a leaf. It hangs head-down in the current, drifting back and forward exactly the way a scrap of weed drifts, and the disguise is good enough that you need a guide to point at it before your eye will accept what it is looking at.
Then you see the head. And the fins. And you spend the rest of the dive finding more.
What a ghost pipefish actually is
Ghost pipefish belong to the family Solenostomidae. They are close relatives of seahorses and true pipefish — same order, same long tube-like snout — but a different family, which is why they are sometimes called “false pipefish”.
They live across the tropical and subtropical Indo-Pacific, from the Indian Ocean to the western Pacific. Most of the year they drift in open water. When it is time to breed they settle onto a reef, a muddy bottom or a current-swept slope where food comes to them, and change colour and shape to match whatever they have settled next to.
Few of them grow beyond 15cm. Most are considerably smaller.
The one fact everyone gets backwards
In seahorses, famously, the male carries the eggs.
In ghost pipefish it is the female.
She is noticeably larger than the male, and her pelvic fins are modified into a pouch she broods the eggs in. If you find a pair — and they are usually in pairs — the big one is the female, and she is the one doing the carrying.
The four species you are most likely to see
Ornate ghost pipefish (Solenostomus paradoxus)
The showiest, and the one most people mean when they say ghost pipefish. Also called the harlequin ghost pipefish. Adults come in white, yellow, red, orange, gold and black, covered in spiny filaments that break up their outline. They grow to about 12cm and turn up between 5 and 30 metres.
Look in crinoids and feather stars first. Also hydroids, and the frayed rope of mooring lines.
Juveniles are almost entirely transparent, with tiny flecks of the colour they will eventually become. They are very small and very easy to miss.
Robust ghost pipefish (Solenostomus cyanopterus)
The leaf impersonator. Usually green or brown, broader-bodied than the ornate, and its whole strategy is to look like a drifting piece of vegetation.
The tell is that the disguise is too good. A real scrap of weed tumbles. A robust ghost pipefish holds its angle and its buoyancy a little too precisely. Once you have noticed that, you start finding them.
Halimeda ghost pipefish (Solenostomus halimeda)
The smallest of them, at around 6.5cm, and named for the Halimeda algae it mimics — usually green, sometimes red or whatever colour its host happens to be. Its head is about as long as the rest of its body, which is the quickest way to tell it apart.
Velvet ghost pipefish (Solenostomus sp.)
Less commonly seen and less commonly photographed, but it turns up, and guests do ask for it by name.
How our guides actually find them
Four habits do most of the work:
- Look for the wrong stillness. Ghost pipefish hover almost motionless, mouth down. Everything around them is moving with the surge; they are not moving quite the same way.
- Search the host, not the fish. Find the feather star, the crinoid, the patch of Halimeda, the clump of weed — then search it properly.
- Expect a pair. If you have found one, the other is usually within a fin’s length. Occasionally the pair is two different species.
- Look shallower than you think. A lot of sightings are between 5 and 15 metres.
This is the part that does not come from a book. Our guides in Lembeh dive the same sites several times a week, every week, and they know which crinoid held a pair last month.
Where to see them
Lembeh Strait, North Sulawesi. The Strait is the reliable one. Black sand, steady nutrient flow and guides who look for this specific animal by default — it is the same skill set that makes the Strait the world’s capital of muck diving. Nudi Retreat has been good for halimeda ghost pipefish.
Bunaken, North Sulawesi. Several sites around Bunaken produce halimeda ghost pipefish in particular. Different diving to Lembeh — walls and clear water rather than muck — so it is a different kind of find.
Amed, Bali. The Pyramids has produced robust ghost pipefish, alongside stonefish and ribbon eels on the same dive. Kubu has had juvenile ornates.
Nusa Penida, Bali. Less of a ghost pipefish destination, but they turn up.
Lembeh and Bunaken sit an easy transfer apart, which is why the Walls and Muck safari pairs them — clear-water walls at one end, critter hunting at the other.
When to go
Here the honest answer is more complicated than most sources admit.
In many parts of their range ghost pipefish are genuinely seasonal, arriving for a few months to breed and then disappearing. That is where the “ghost” reputation comes from — they settle on a site for days or weeks and then are simply gone.
In Lembeh they are found year-round, but in pulses.
Some weeks the ornates are everywhere; other weeks you work for a single robust. Nobody can promise you a ghost pipefish on a given day, and anyone who does is guessing.
Photographing them
They are a rewarding subject and a frustrating one. They hold still, which helps. They are also small, low-contrast against their host by design, and often tucked inside a crinoid that will close around them.
Shoot slightly down and across to separate the fish from its host, and be patient with focus — autofocus hunts badly on an animal specifically evolved to not have edges.
Our guides in Lembeh, Bunaken and Amed look for this animal by default. Tell us when you want to dive and we will tell you honestly what is around.
Q&A
Ghost pipefish questions, answered
A small fish in the family Solenostomidae, related to seahorses and true pipefish but in a different family. They hang head-down, mimic leaves, algae or feather stars, and rarely exceed 15cm.
No. Ghost pipefish are Solenostomidae; true pipefish are Syngnathidae. They share an order and a snout shape, which is why ghost pipefish are sometimes called false pipefish.
Most commonly the ornate (harlequin), robust and halimeda ghost pipefish, plus the velvet.
The female, unlike seahorses. She is larger than the male and broods the eggs in pouch-like modified pelvic fins.
They are present year-round in the Lembeh Strait, though numbers come in pulses rather than to a reliable calendar.
The Lembeh Strait is the most consistent. Bunaken produces halimeda ghost pipefish, and Amed has robust ghost pipefish at the Pyramids.
