Melibe Colemani: The Elusive Ghost Nudi of North Sulawesi

If you’re planning a scuba diving trip to Indonesia, there’s a good chance you’ve heard whispers of a translucent, alien-like creature lurking in the muck. Meet Melibe colemani, better known as the ghost nudi of North Sulawesi. This surreal, almost mythical nudibranch haunts the imagination of macro photographers and nudibranch lovers around the world.

This isn’t your average sea slug. With a gelatinous, nearly invisible body, a bizarre feeding hood instead of a mouth, and movements that resemble a slow-motion space ballet, the ghost nudi is one of the most unique marine species you’re ever likely to encounter.

And the good news? You don’t need to travel to a galaxy far, far away to find it. We sometimes catch a glimpse of these ethereal creatures around Murex Bangka in North Sulawesi! In this article, we’ll reveal everything you need to know before you go.

What Is Melibe Colemani?

Described in 2009 and named in honor of renowned nudibranch naturalist Neville Coleman, Melibe colemani is part of the Tethydidae family. It stands apart from more commonly encountered dorid or aeolid nudibranchs in both its appearance and its behavior.

Rather than feeding on hydroids or sponges like many of its cousins, M. colemani uses a large, expandable oral veil (a sort of hood-shaped appendage) which it sweeps across the substrate to trap plankton and benthic microfauna. This veil functions like a miniature trawling net, and also gives the animal its unmistakable silhouette when fully extended.

So how do you spot one of these elusive creatures? Here’s a few identifying features to look out for when diving in North Sulawesi:

• Oral veil: Circular and semi-rigid, used in a slow sweeping motion to capture prey.
• Body: Semi-transparent and gelatinous with minimal coloration—excellent camouflage against coral rubble and algae.
• Cerata: Reduced and irregular, unlike typical nudibranch forms—often mistaken for detritus or polyps.
• Movement: Undulating, almost floating movement, particularly in low currents.

Because of its delicate body and cryptic coloration, spotting a ghost nudi is no easy task. It takes a trained eye, patience, and a slice of luck. But for those divers who find it, the reward is an unforgettable, otherworldly encounter.

Where Can You See the Ghost Nudi?

While ghost nudi have been spotted in the Philippines, Papua New Guinea, and occasionally in the Lembeh Strait, Bangka Island’s unique habitat matrix appears to be a consistent hotspot for this species. We have one dive site in particular where we often see Melibe colemani, so you stand a good chance of encountering one when you visit Murex Bangka.  

With a mixture of coarse coral rubble, encrusting algae, and relatively gentle currents, the region provides an ideal microhabitat for otherworldly visitors like Melibe colemani. These ethereal ghost nudis are typically found at depths of 12–25 meters, often in sheltered slopes or between bommies where fine detritus accumulates. Their cryptic behavior and translucency mean they’re frequently overlooked, even when in plain view.

To improve your chances of finding one:

• Focus on rubble zones with rich algal growth.
• Look for movement, not color. Keep a sharp eye out for the rhythmic undulation of that distinctive oral hood.
• Dive slow, and let your guide take the lead. Local spotters at Murex Bangka are trained to search for signs of nudibranchs and various other critters. Their sharp eyes are your best friend on a ghost hunt.

Bangka is known for its stunning soft corals, crystal-clear waters, and rare macro life. Here, divers have reported frequent sightings of ghost nudis gliding across the substrate, feeding with their trademark translucent hoods unfurled like alien jellyfish.

Why Is Melibe Colemani So Fascinating?

Nudibranchs as a group are already pretty weird and wonderful, but Melibe colemani takes this to a whole new level. Even seasoned divers who’ve seen it all get excited when a ghost nudi makes an appearance. It’s the kind of find that elevates any scuba diving holiday into something truly extraordinary.

As a cryptobenthic species with highly specialized feeding and habitat preferences, the presence of Melibe colemani is also a clear indicator of ecosystem health. Its diet—primarily plankton and small benthic organisms—indicates a functioning food web in reef-adjacent habitats.

This makes the continued presence of ghost nudis around Bangka a promising sign for marine biodiversity in the region. It’s also a compelling case for the protection of overlooked “transition zones” such as coral rubble fields, which are often degraded by anchor damage, sedimentation, or bottom trawling elsewhere in the Coral Triangle.

The Bigger Picture: Why Critters Matter

Sightings of Melibe colemani are more than just a personal triumph—they’re emblematic of how diverse and fragile our marine ecosystems are. The fact that these otherworldly species can still make their home in places like Bangka and Lembeh is a positive indicator of ecosystem health in these locations—and a reminder that we must protect them.

Conserving our coastal oceans is critical, not only for the survival of ghost nudis but for the whole complex web of life supported by coral reefs. Sustainable tourism in conservation-focused dive resorts like Murex plays a key role in preserving these delicate habitats. To learn more about our conservation efforts, please click here.

Dive With Murex Bangka: Your Best Chance to Spot a Ghost

At Murex Bangka, our guides know the local dive sites like the back of their hand. While no sighting is guaranteed, this location—and this team—represent your best chance of encountering Melibe colemani in the wild. Each of our guided dives are led by specialists familiar with the region and its many micro wonders.

So, whether you’re adding to your nudibranch bucket list, building your macro photo portfolio, or seeking something truly extraordinary—diving Bangka puts you in the right place at the right time.

Looking for a complete experience of diving in North Sulawesi? Our Passport to Paradise program connects the coral reefs of Bangka with Bunaken’s walls and Lembeh’s muck sites in a single, seamless dive holiday.

Ready to Meet the Ghost Nudi?

If the idea of diving with the ghost nudi has sparked your curiosity, it’s time to start planning your next scuba diving vacation. With Murex Resorts, you can enjoy easy access to North Sulawesi’s top dive sites, support from expert guides, and comfortable accommodation in one of the region’s top PADI dive resorts.

Book your trip today and take a deep dive into the weird and wonderful world of Melibe colemani—North Sulawesi’s very own ghost of the sea.