Scientists discovered a tiny new fish species in the Red Sea but have never found it again, suggesting it may live mostly on deeper reefs that remain largely unexplored.
In Greek mythology, Charon ferried the dead across a river into the underworld. People were traditionally buried with a coin to pay for the crossing. That tradition helped inspire the name of a newly described fish species from the northern Red Sea, Charon’s pygmygoby (Trimma charon).
“One of the most striking features of the new species is the golden spots scattered across its tail fin,” said study leader Viktor Nunes Peinemann of King Abdullah University of Science and Technology (KAUST) in Saudi Arabia. “They cover most of the fin and resemble small gold coins.”
The tiny fish is translucent, with a broad orange-red stripe and an unusual four-part eye. The two known specimens measure just 12 and 17 millimeters long, roughly half an inch and two-thirds of an inch.
A possible relative across two oceans
The new species resembles the pallid pygmygoby (Trimma anaima), a fish found from East Africa to the Pacific but never recorded in the Red Sea. Genetic data suggest the two are close relatives, although further work is needed to confirm that relationship.
“While one species seems to have spread across much of the Indian and Pacific Oceans, its closest relative appears to have stayed in the Red Sea and evolved separately for millions of years,” said Peinemann.
Two specimens hint at a deeper habitat
Researchers collected the two specimens in May 2023 at Walih Island, at the entrance to a cave on a steep reef slope. They were found 30 meters, about 98 feet, below the surface, the maximum depth of the team’s scientific diving. Extensive searches of similar habitats since then have produced no further sightings. “So far, the entire species is known from only a single encounter and two specimens,” said Peinemann.
The team suspects that the encounter took place at the shallow edge of the species’ range. The fish may be more common on largely unexplored mesophotic reefs below 30 meters, where sunlight is faint. That possible habitat provides another connection to its mythological namesake.
“These dark, deeper, unexplored reefs could be viewed as a kind of ‘underworld’ beneath the shallow, well-lit, and better studied reefs most of us are more familiar with,” he said.
“Red Sea reefs below that depth almost certainly hold more undiscovered gobies.”
Many pygmygobies appear confined to the Red Sea
The discovery brings the number of known Trimma species in the Red Sea to 11, making it the region’s most species-rich goby genus. At least nine appear to live nowhere else in the world. To help researchers distinguish them, the paper provides an illustrated identification key to all 11 species, along with photographs and field notes describing where each lives.
The study is published in the open-access journal ZooKeys. Peinemann is based in the Marine Science Program within KAUST’s Division of Biological and Environmental Science and Engineering. His co-authors are Matthew D. Tietbohl Talas and Michael L. Berumen of KAUST, and Sergey V. Bogorodsky of the Senckenberg Research Institute and Natural History Museum Frankfurt, Germany.
“Knowing which species are present, how to accurately identify them, and where they live, is the most foundational step to building a stronger understanding of these species and ecosystems,” said Peinemann. “They still have many secrets and deserve much more attention.”
Reference: “Trimma charon, a new species of pygmygoby (Teleostei, Gobiidae) from the Red Sea with a key to the Red Sea species of the genus” by Viktor N. Peinemann, Sergey V. Bogorodsky, Matthew D. Tietbohl Talas and Michael L. Berumen, 24 September 2026, ZooKeys.
DOI: 10.3897/zookeys.1293.204097
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.