A new population of the world’s rarest fish, the Red Handfish (Thymichthys politus), has been found off the Tasmanian coast

The Red Handfish (Thymichthys politus) is believed to be the rarest species of fish in the entire ocean based on our knowledge of it, and up until very recently there has only been one location where this incredible fish has been found!

A Red Handfish with its red morph. Image by Rick Stuart-Smith / Reef Life Survey. Posted with the Creative Commons Attribution 3.0 Unported (CC BY 3.0).

If you want to see a Red Handfish for yourself, you’ve got to head to the eastern coast of Tasmania, an island just south of Australia. The exact location of the population of Red Handfish is close to Frederick Henry Bay, an area that is much used by surfers. Somewhere close to this bay there is a 50x20 meter square that is the home to between 20 to 40 Red Handfish. The size is comparable to two tennis courts stacked next to each other, so it is easy to understand why we haven’t really found lots of populations.

The Red Handfish are really good-looking fish with either a dark red, or a yellow/pinkish color palette, and these are two distinct morphs of the same species. It would be very easy to assume these to be two different species if you didn't know about them, but they are in fact the same.

A new population has been found by divers from IMAS and the citizen science project Reef Life Survey (RLS)

A diver reported finding a Red Handfish a few kilometers away from the already known locations, and was met with disbelief. However, a team from Australian Institute for Marine and Antarctic Studies from University of Tasmania, and citizens from the project Reef Life Survey went to investigate the area, and after two days they were on the brink of giving up. However, just before deciding to head back they found a new member of the most rare fish species in the world!

Also a Red Handfish, but this is the yellow morph version of it. Image by Rick Stuart-Smith / Reef Life Survey. Posted with the Creative Commons Attribution 3.0 Unported (CC BY 3.0).

After further investigation, the team concluded that this new site is also home to 20 to 40 individuals, and is about the same size as the other location. A nice surprise was that the habitat was not what the scientists had expected it to be, meaning that the Red Handfish might not be as picky about its habitat as expected! This is great news from the perspective of finding even more populations, but it also means that it will be more difficult to find them.

The exact location of the new population has not been made public knowledge, and the group hopes that it will stay that way until the area can be legally protected in order to prevent anyone from harming the fish.

So what exactly are handfish?

The handfish (Family Brachionichthyidae) are benthic (bottom-dwelling) anglerfish that are only found in the waters close to Australia and Tasmania. What is really unique about them is that they uses their fins to walk on the ocean floor instead of swimming like most other fish do. These fins are looking a lot like the hands of us humans, which is why they got their name in the first place.

A spotted handfish (Brachionichthys hirsutus). Image by Rick Stuart-Smith / Reef Life Survey, posted with the Creative Commons Attribution 3.0 Unported license.

Most of the handfish are threatened by things such as climate change that is heating up the ocean, and the Spotted Handfish in the image above is considered Critically Endangered by the IUCN Red List, which means that it will most likely face extinction somewhat soon. Another species of handfish, Ziebell's Handfish (Brachiopsilus ziebelli) also used to be a contender for the rarest fish in the world, but this species is now expected to be extinct on the basis that it has not been seen for a decade.

Could there be a lot more of these fish in the ocean?

Since we have only found one (now two) populations in the last 15 years, despite a lot of people looking for them, it’s safe to assume that they are very rare. Scientists believe that they only live in pretty shallow waters, so it is also unlikely that they around found far from the shores. However, seeing as the scientists had to spend two days searching for them even after knowing about the location that was indeed their habitat, I can only begin to wonder how many populations there actually are.

I’m not saying that this is a common fish by all means, but I am personally beginning to think that it might be a bit less rare than some people claim it is, based on the fact that it seems to be extremely difficult to actually find on the sea floor. Maybe new findings like this one will lead to it not being considered the rarest fish in the world anymore? We can hope so, because if there are only two small populations left, the future of the Red Handfish is looking very grim..

Thanks for reading

Thanks for reading about the Red Handfish! If you want to learn more about them, then I suggest checking out their profile on reeflifesurvey.com as well as their profile on Fishes of Australia. You can also see the announcement of the newly discovered population on University of Tasmania’s website. These three links should have most of the known information about this fish species, but keep in mind that it's very rare and unstudied, so we don't really know too much about it in the first place. Anyway, I hope everyone has a great Friday, and make sure to leave a comment below to join the discussion!

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