Red Handfish: New Population of World's Rarest Fish Discovered by Accident

1_24_Red Handfish
The red handfish grow to about four inches in length. Mark Green/Thor Carter/CSIRO Marine Research

Divers have discovered a new population of what may be the world's rarest fish, doubling the number believed to exist. What's more, the discovery almost didn't happen.

Only 20 to 40 of the critically endangered red handfish were thought to exist. The strange little fish wriggles, rather than swims, along the seabed off the coast of Tasmania, Australia, and has distinctive red fins that look like hands. The discovery of another population a few miles away from the first has given hope to scientists that other species may be swimming below the radar.

"It's got to be close to the rarest fish in the world," scientist Rick Stuart-Smith says in a video published by the Institute for Marine and Antarctic Studies (IMAS). "Finding this second population is a huge relief, as it effectively doubles how many we think are left on the planet."

Caught Red-Handed

After a member of the public reported seeing a single handfish off the coast of southeast Tasmania, divers from IMAS and the citizen science Reef Life Survey took to the waters to search for more. They searched an area a few miles from the known population in Frederick Henry Bay.

At two hours into a three-and-a-half-hour dive, IMAS technical officer Antonia Cooper and a team of seven divers were about to give up. "We were all looking at each other, going, well, this is not looking promising," Cooper said. The team had seen no sign of the crawling fish.

Frustrated by the fruitless trip, she signaled to her diving partner to call off the search. While waiting for the team to stop swimming, she aimlessly flicked at some nearby algae. Lo and behold, Cooper had accidentally uncovered one of the elusive fish.

This spot allowed the team to narrow down their search area. They went on to identify eight individual creatures, estimating that 20 to 40 fish inhabit this newly discovered site. Both sites are about 150 feet by 60 feet and are located a number of miles apart.

Sociable Fish

The discovery has taught scientists the fish may be more adaptable than previously believed. Stuart-Smith explains: "We've already learned a lot from finding this second population because their habitat isn't identical to that of the first population, so we can take some heart from knowing red handfish are not as critically dependent on that particular habitat.

"Because each population is so small, it's an indication that they are very sociable animals."

The discovery brings hope that certain species believed to be extinct might be crawling along beneath the radar. One fish in particular, the Ziebell's handfish, has not been seen for over a decade and is assumed to be extinct.

Stuart-Smith adds: "The only thing that would have been more exciting last week would have been finding the Ziebell's and finding out that they're not extinct."