The discovery of the Sodwana seahorse (Hippocampus nalu), Africa’s first pygmy seahorse

I am beyond excited to share the news that with a fantastic team of colleagues, we described a new species of pygmy seahorse!!! Hippocampus nalu, or the Sodwana pygmy seahorse in normal language, is the 45th seahorse species to be described, and the first pygmy seahorse species found in African coastal waters. It’s gorgeous and cute and very tiny.

To explain the story of how such a discovery happens, we wrote an explainer in The Conversation. Just so you wouldn’t have to do effort of clicking the link, I am also sharing the article below, which was co-written by myself, Louw Claassens, Graham Short, and David Harasti. All pictures provided are by Richard Smith.

Before you read this article, pause for a moment and look at the nail on your little finger. That’s about the size of a new species of seahorse discovered in the waters of Sodwana Bay, South Africa, which falls within the iSimangaliso Wetland Park, a World Heritage Site, in KwaZulu-Natal province.

Hippocampus nalu grows to a maximum size of just 2cm. It is the first pygmy seahorse ever discovered in African waters. Our team has conclusively demonstrated that Hippocampus nalu is physically and genetically distinct from the seven known species of pygmy seahorses. Its nearest relatives are found more than 8,000 km away in the Pacific Ocean.

Hippocampus nalu - South African pygmy seahorse, Sodwana Bay

An adult male Sodwana seahorse (Hippocampus nalu). Credit: Richard Smith

Seahorses are threatened all around the world. Many species are at risk of becoming extinct because of human activities such as bottom trawling, over-fishing, and habitat destruction. As a result, several species are listed on the IUCN Red List of Threatened Species. However, to date no pygmy seahorses are considered threatened – because we simply do not know enough about them. By discovering more species, and learning more about these tiny creatures, scientists can offer advice on how best to protect them.

Pygmy seahorses can also provide an important boost for tourism: scuba divers love these small species and are willing to travel far and wide for a chance to see them. If coastal communities and scuba divers alike are taught about the best ways to protect these species and others in the oceans, there can be huge economic and social benefits.

The most astonishing part of this discovery is that it didn’t start in a laboratory, or with keen scientific minds assessing the likelihood of finding a pygmy seahorse in African waters. Instead, it began with a photograph.

Tracking the seahorse

Dr Louw Claassens and Dr Dave Harasti arrived in Sodwana in early 2018 looking for an entirely different animal: a seahorse-like species called a pygmy pipehorse. But then a local dive guide named Savannah Olivier showed them a photograph of a very small seahorse. The scientists recognised it as a pygmy seahorse, which are supposed to live an entire ocean away. South Africa is home to four other seahorse species, but this was the first time a pygmy seahorse had been observed in South Africa, let alone Africa.

Nine months later Louw returned to Sodwana Bay, this time accompanied by Dr Richard Smith, a pygmy seahorse expert. They, with Olivier, found a pair of the tiny pygmy seahorses along a rock face at about 15m depth. The little creatures were grasping on to slivers of algae amid raging surging seas. The reefs of Sodwana Bay are exposed to the swells of the Indian Ocean, very unlike the more sheltered coral reef settings in the tropical Pacific where the other known pygmy seahorses are found.

Later they even found a tiny juvenile measuring just a centimetre in length, which was dwarfed by a diver’s finger.

Juvenile Hippocampus nalu - South African pygmy seahorse, Sodwan

Juvenile Hippocampus nalu – South African pygmy seahorse, Sodwana Bay. Credit: Richard Smith

Finding the seahorses was only the first step in describing the new species. The rest of the team now got to work. Graham Short, a researcher at the Australian Museum and California Academy of Sciences, compared the mystery seahorses with other pygmy seahorse species by looking at their characteristics under a microscope, as well as a powerful CT scanner. Dr Mike Stat, a geneticist from Australia, used genetic methods to test how distinct it was from other species. Through combined team efforts, we confirmed that the Sodwana pygmy seahorse was a new species and could give it an official scientific name.


CT scan of the Sodwana seahorse (Hippocampus nalu). Credit: Graham Short

The name “nalu” has three layers of meaning. In the local isiXhosa and isiZulu languages it means “here it is”, to show that the species had been there all along until its discovery. “Nalu” is also the diver Savannah Olivier’s middle name. Finally, “nalu” means “surging surf, wave” in Hawaiian, which hints at the habitat the species lives in.

More to learn

The discovery of the Sodwana pygmy seahorse is exciting for more than just its scientific value. It provides new insights into the global distribution of these tiny fish and paves the way for further exploration in other locations. Only a handful of research publications focused on the ecology of pygmy seahorses exist, so anything we can learn more about these critters will help the future conservation of this unique group.

Finding a species like Hippocampus nalu also shows how little we know about Africa’s marine biodiversity, and how much more is left to discover. It highlights how important the observations of keen amateurs are to help scientists. If a keen fisherman did not consider a strange looking fish caught off the south coast of South Africa worth sharing with Marjory Courtney-Latimer in 1938, the discovery of the coelacanth, a living fossil, might never have happened.

Similarly, without a diver’s sharp eyes and an expert’s initial questions, the world would still not know that the Sodwana pygmy seahorse exists. As scientists, being open to questions from the general public not only helps inform non-scientists, but can also help us make new discoveries.

Hippocampus nalu - South African pygmy seahorse, Sodwana Bay

 A female Hippocampus nalu. Credit: Richard Smith

Time for something new

I never liked going to school. Not as a kid, not as a teenager, and not even as a young adult. Maybe I just disliked being bored so often? Even in the classes I was interested in, I felt that just absorbing all the knowledge in world was not exciting. My impression was that science already knew everything and that new discoveries were pretty much impossible. That science had somehow “stopped”.

Well, let me tell you one thing, it most definitely has not! I was not learning “all the knowledge in the world”, in fact LOTS of new things are discovered all the time! Since this blog is about ocean critters, let’s look at some of the critters that have recently been discovered. In the last year alone, new seahorses, frogfishes, gobies, jawfishes, and many other species have been discovered. So if you thought you’d seen it all, think again 😉

Seahorses and relatives

A new species of pygmy seahorse was described 3 months ago by Graham Short and colleagues. This ridiculously cute little seahorse lives in Japan and is called Hippocampus japapigu (=Japanese pig seahorse). These little wonders are less than 2cm in size and have a wonderful honeycomb colour pattern. Unlike some other pygmy seahorses, the Japanese pygmy seahorse does not live in seafans, instead it can be found in hydroids, algae, or soft corals.


The newly describe Japanese pygmy seahorse (Hippocampus japapigu). Photo: Richard Smith

Even more recently, less than a month ago, another new pygmy seahorse species was discovered in South Africa. The first ever pygmy seahorse in South Africa! Dive operators in the Sodwana Bay region had found this small seahorse and asked pygmy seahorse expert Richard Smith about it. Together with IUCN seahorse expert Louw Claassens he went for an expedition and has confirmed the new species. It has not got a name just yet, but should be officially described sometime next year.

During the same expedition, Richard and Louw also found a new species of pygmy pipehorse! You might have never heard of pipehorses, but they are just fantastic. Sort of like a seahorse that disguised itself as a pipefish, or maybe the other way around?

SA pipehorse

A newly discovered, still unnamed pygmy pipehorse from South Africa. Photo: Richard Smith


Big news from Australia as well! A new frogfish species was described in the journal Copeia this week. The Narungga frogfish (Histiophryne narungga) is found in South and West Australia, and was named after the indigenous people living in the area. The beautiful new frogfish lives mostly in shallow water, where it does what frogfishes does best: mimicking sponges or other benthic organisms, hoping to catch unsuspecting prey that swims by. This small (less than 10cm), new frogfish is very much on my “critters to see before I leave Australia”-wish list!

H narungga

Narungga frogfish (Histiophryne narungga): A new Australian frogfish species. Photo: Rudie Kuiter

The researchers describing the Narungga frogfish, Rachel Arnold and Theodore Pietsch, are pretty much the rock stars of the frogfish world. Together they have described 9 new frogfish species in the last 10 years, the most famous of which is the Psychedelic frogfish!


I’ll be honest, for someone who studies cryptobenthic fishes, I don’t know nearly enough about gobies. Luckily, other researcher do know a lot about gobies and they seem to be good at finding new species as well. This year a new species was discovered from the west Pacific Ocean. The polkadot dwarf goby (Eviota maculosa) lives in Indonesia, Australia and Pohnpei. Its small size, less than 2cm, probably explains why it has taken researchers so long to realise this was an undescribed species.

Eviota maculosa

Eviota maculosa, a new goby species from the west Pacific. Photo Mark Erdmann


If you are not a keen muck diver or underwater photographer, you can be forgiven for not knowing about jawfishes. These cryptic fish live in holes in the sand and don’t venture out very often. Most notably, they are “mouthbrooders“, fish that hatch their eggs in their mouths. This week, two new jawfishes were described from Brazil. Thiony’s jawfish (Opistognathus thionyi) and the Brazilian dusky jawfish (Opistognathus vicinus) both seem to be endemic to Brazil, meaning they do not occur anywhere else. Thiony’s jawfish seems to live deeper than the Brazilian dusky jawfish, but otherwise, not much else is known about these new species.

O thionyi

Thiony’s jawfish (Opistognathus thionyi) from Brazil. Photo: Raphael M. Macieira

O vicinus

Brazilian dusky jawfish (Opistognathus vicinus) from Brazil. Photo: Raphael M. Macieira

This list of new critters is by no means complete. Many more species have been recently discovered, and many more will be discovered in the future. I find it very exciting that science isn’t ready yet and that there is so much more of the amazing natural world left to discover. If that doesn’t make you want to become a scientist, I don’t know what will… (We often have cookies in the office if that’s more your thing?)

Little known facts about seahorses

I have been reading up about seahorses recently and discovered some interesting little bits of information I could not help but share. While seahorses seem to be a big favourite for divers and non-divers alike, we actually know surprisingly little about them. Some of their strange quirks are well known. The fact that the males get pregnant is probably one of the favourite and most retold bits of knowledge about them. I want to go a bit further and more interesting than that, so let’s get started.


The fused jaw of a seahorse (Source)

Seahorses belong to the family of Sygnathidae, which  translates as “fused jaws”. What this means is that all seahorses and pipefishes have jaws that are stuck together, they can’t open them anymore. So if you were to imagine eating like a seahorse, try gobbling up your salad, steak, pizza, apple,… with clenched jaws, while only using your lips to help you suck the food in. A good thing seahorses do not have teeth, as that would make it even more difficult!

Best of Dauin_Seahorse Estuary_MDB

Hippocampus taenopterus, getting ready to growl

Another quirky thing seahorses do, is that they make noise. They make two distinct types of sounds: “clicking” and “growling”. I absolutely love the idea of a growling seahorse! It seems they do this when they are stressed out and it might even be some sort of escape mechanism to startle predators. Most likely because those predators would be laughing too hard because a seahorse just growled at them… The clicking sounds are mostly used during courtship and mating, so not only do seahorses growl to chase away predators, they also serenade their partners to get them in the right mood. Strange little critters indeed.

To keep up with the strangeness, have you ever wondered how strange the tail of a seahorse actually is? Probably not, I definitely hadn’t before reading this article.  The tails of most animals are round, but nearly all seahorses have square tails. As it turns out, this square shape is better at grasping and holding items. At the same time it offers a higher resistance to crushing than a round tail would. So perfect for a camouflaged critter which spends most of its time clinging on to objects, pretending to be something it is not to avoid getting eaten by predators.

Seahorse tails

Different 3D printed models of seahorse tails (Source)

Best of Dauin_Seahorse thorny_MDB

Hippocampus histrix

The objects seahorses hold onto can be anything, usually they cling on to objects like seagrass, algae, gorgonian seafans, etc. But they do not seem to be very picky at all. This article showed how seahorses living in areas with a lot of plastic actually use that plastic as camouflage. The seahorses even changed their colour to resemble the colour of the plastic and the spots on it. Unfortunately I cannot put the original pictures online due to copyright issues, so if you want to see them, follow this link. Since seahorses don’t really mind what they hold on to, artificial structures can be used to provide habitat for them when their natural habitat has been destroyed. This way populations can continue to exist until the natural vegetation has recovered.

Loss of habitat is one of the risks that endanger seahorses, the trade for traditional Chinese medicine is another big threat to them. IUCN has listed 7 species as Vulnerable and one species as Endangered, but most species have either not been assessed or we lack the data to assess whether or not they are endangered. To combat the illegal trade and offer some means of protection, all seahorses are listed with CITES, which means trading them is strictly controlled. One of the simple rules used to do this, is a size limit of 10cm. This size ensures that most traded seahorse species are mature individuals who can reproduce and that juveniles are left alone.


Hippocampus pontohi

The fact that we don’t really know how many species of seahorses exist, makes protecting them hard. Estimates of the number of seahorse species range from 40 to 48 species. It is quite likely new species are still waiting to be discovered, though the opposite might happen as well. Two species of pygmy seahorses (Hippocampus severnsi and Hippocampus pontohi) were described in 2008. But recent genetic analyses showed that they are actually the same species which comes in different colour variations.


If you want to know more about seahorses or just have a good laugh, check out this great video from Ze Frank with some more true facts about seahorses.

Dragons, Currents and Hidden Gems

Komodo tripThere hasn’t been much activity on the blog recently, mostly since I’ve been stowed away on various boats exploring the marine life around the Komodo Islands. I just got back from a very comfortable liveaboard trip ran by Safari Bali, who have been kind enough to let me hop on the Sea Safari 7 as resident marine biologist. In return for the trip I do presentations for the guests, help them identify creatures they’ve seen, or generally answer any ocean-related question they might have. A great deal if you ask me, since it gives me the chance to do research in one of the best dive destinations in the world.

Komodo has been one of my favourite spots since I dived it the first time six years ago. The enormous diversity in marine life and dive sites is hard to find anywhere else. Raja Ampat might have more species, but to me Komodo is more interesting. There are more muck sites, stronger currents, lots of weird critters and they’ve got dragons…it’s hard to top dragons.

Komodo Dragon

Komodo Dragon (Photo by Jennifer Tambosco)

Komodo national park was established in 1980 and was declared a World Heritage Site in 1986. The park was originally designed to protect the endemic Komodo Dragons. They are the world’s largest reptile and are only found in the Komodo National Park and a few areas on the west coast of Flores. It was quickly recognised that the diversity in the surrounding ocean was a lot bigger than on land and protection was put in place for the marine environment as well.

Ghostpipefish party, six Solenostomus paradoxus hanging out

Ghostpipefish party, six Solenostomus paradoxus hanging out

Life under water is governed by the strong currents around the islands. The Komodo islands form a passage between the Pacific and Indian Ocean, the water flowing between them causes the famous currents in the area. These currents bring in important nutrients on which the marine life depends and it doesn’t take many dives in the area before you realise just how much of an effect they have. Diving in Komodo is always exciting, not just because you’re often flying around under water at exhilarating speeds, but also because of the enormous diversity of life that is created by these currents.

Pygmy Seahorse (Hippocampus bargibanti)

Pygmy Seahorse (Hippocampus bargibanti)

Explaining just how diverse and exciting diving in Komodo is very difficult. To make life easier for myself, here is an excerpt from my logbook from the trip: manta rays, sharks, eagle rays, frogfishes, octopuses, turtles, napoleon wrasses, seahorses, ghostpipefishes, giant trevallies,… On top of that reefs are generally very healthy, with huge clouds of reef fish hovering around them. From the boat we’ve seen at least 3 different species of dolphins and a whale. In this crazy fish soup I spent most of my time looking for pygmy seahorses, which greatly confused some of the other divers on board. Why bother with critters 1cm in size if you’ve got manta rays and sharks flying overhead? This is a fair point, but I am trying to get an idea of how many pygmy seahorse are out there, so the manta rays will have to wait… In all fairness, I might have gotten distracted a few times, but who can blame me for that?

Selfie time with the local kids :) (Photo  by Jennifer Tambosco)

Selfie time with the local kids 🙂 (Photo by Jennifer Tambosco)

I am also using these trips to explore other sites in the area for critters. There are over 17000 islands in Indonesia and the best way to explore them is by boat. Some of the places we dived at along the way are absolutely beautiful and still pretty unexplored. One of my favourites was Sangeang, an active complex volcano (it has 2 cones) with 2 small villages on its slopes that specialise in traditional boat building. The dive sites around Sangeang are phenomenal; great muck diving, loads of critters, and mostly unexplored. Another gem (though better known) is the south of Komodo. The waters around Nusa Kode are cold (20°C) but very rich, it had some of the highest concentrations of anemonefishes I’ve seen in Asia. A night dive in the bay made it in my top 3 of best night dives ever, I won’t bore you with details, but if you like weird and wonderful critters it’s an absolute must!

Bontoh village, Sangeang volcano in the background

Bontoh village, Sangeang volcano in the background