Wolverine fish and blind eel among 212 new freshwater species

Scientists are celebrating 212 “new” freshwater fish species, including a blind eel found in the grounds of a school for blind children and a fish named Wolverine that is armed with a hidden weapons system.

The New Species 2021 report, released by the conservation organisation Shoal, shows just how diverse and remarkable the world’s often undervalued freshwater species are, and suggests there is plenty more life still to be discovered in the world’s lakes, rivers and wetlands.

“It’s fascinating that over 200 new freshwater fish species can be described in just a single year,” said Harmony Patricio, Shoal’s conservation programme manager. “You might see this level of new discovery for organisms like plants or insects, but not really for vertebrates.

“It means there are still hundreds and hundreds more freshwater fish out there in the world that scientists don’t know about yet,” she said. “Also, many of the newly described species have pretty unique and unexpected traits.”

One of those unexpected physical traits is the hidden weapons system of the Wolverine pleco (Hopliancistrus wolverine), which earned it an X-Men-inspired name. “This species has strong lateral curved spikes called odontodes tucked under the gill covers that can be extended to jab anything that tries to mess with them,” Patricio said.

“Other related species in the same family, even those with big spines, aren’t known to demonstrate such behaviour. The researchers who described this species ended up with quite a few finger injuries while collecting specimens from the wild.”

An average of four freshwater fish species a week were newly described last year. Other findings include the bright red Mumbai blind eel (Rakthamichthys mumba), which has no fins, scales or eyes, and was found at the bottom of a well in the grounds of a school for blind children; the tiny, translucent Danionella cerebrum, discovered in southern Myanmar and only slightly larger than a thumbnail; and the colourful Kijimuna and Bunagaya gobies (Lentipes kijimuna and Lentipes bunagaya) in southern Japan, named after woodland spirits in Okinawan folklore.

Each of the 212 discoveries offers new possibilities for scientists to increase their understanding of freshwater species, including their anatomy, evolution and the connections between other creatures and their habitats.