Freshwater fish - Artensterben

Europäische Süßwasserfische - Plötze und Rotfeder (Heinrich Harder / Emil Walter)

Historic depiction of European freshwater fish (Heinrich Harder)—the new IUCN Red List (2025) shows how severely the condition of European waters has deteriorated. Image: Walter, Emil, Public domain, via Wikimedia Commons

17. April 2026 Doreen Fräßdorf

IUCN Red List 2025: Europe’s freshwater fish in crisis—nearly 60% under pressure

Europe’s rivers and lakes are among the most heavily altered ecosystems in the world. Hardly any body of water remains unaffected—many have been regulated, dammed, or fundamentally transformed by human use. The updated IUCN Red List (2025)—the most comprehensive assessment of European freshwater fish in 15 years—makes the consequences of

Bodensee-Kilch (Coregonus gutturosus) und ein Tiefseesaibling (Salvelinus profundus)

Historic depiction of the Lake Constance whitefish with the Lake Constance deepwater char (bottom left), which was rediscovered in 2016. Both lived in the deep areas of Lake Constance — a habitat that was severely affected by eutrophication in the 20th century. (© Walter, Emil, Public domain, via Wikimedia Commons)

15. April 2026 Doreen Fräßdorf

Lake Constance Whitefish: An example of species loss in alpine lakes

Species or just a form? The Lake Constance whitefish or kilch belongs to the genus Coregonus—a group of salmonids found in cool, oxygen-rich waters across the Northern Hemisphere. In Europe, they are known as Felchen, Maränen, Reinanken or Renken (whitefish). Hardly any other fish group is considered as taxonomically difficult: many forms have arisen only

Flusspferd als eingeschleppte Süßwasser-Megafauna

Hippopotamus – This mammal, weighing up to three tons, is one of the largest freshwater inhabitants on Earth. In Colombia, feral populations exist today after animals escaped from a private collection and spread along the Magdalena River. (© Joachim Huber, CC BY-SA 2.0, via Wikimedia Commons)

10. March 2026 Doreen Fräßdorf

Introduced freshwater megafauna: Benefits and risks of large animals in rivers and lakes

Rivers and lakes are home to some of the largest animals in inland waters—from giant catfish, sturgeons, salmon, and carp to turtles and crocodiles. However, many of these species have been deliberately introduced by humans into new regions. A new global study in the journal One Earth systematically examines for

Qutang-Schlucht am Jangtse (Changjiang) in der Drei-Schluchten-Region in China

The Qutang Gorge on the Yangtze (Three Gorges region): heavily burdened for decades—a study now shows the first signs of ecological recovery. (© Tan Wei Liang Byorn, CC BY 3.0, via Wikimedia Commons)

21. February 2026 Doreen Fräßdorf

Hope for the Yangtze: study shows how a fishing ban is reviving the river

The Yangtze River is Asia’s longest river at over 6,300 kilometers and the third-longest river in the world. For millennia it was among the world’s most species-rich freshwater ecosystems. It supplied people, animals, and entire cultures with water, food, and habitat—and formed the ecological backbone of large parts of China.

Wiederentdeckung: Killifisch Moema claudiae

Tiny, vividly colored and almost lost: Moema claudiae — shown here as a male (top, 3.8 cm) and a female (bottom, 3.6 cm) — was rediscovered in 2024 after more than 20 years. This killifish species grows to only about four centimeters and survives in temporary rainy-season pools of the Bolivian Amazon region. (© Drawert & Litz (2025), Nature Conservation, CC BY 4.0)

17. November 2025 Doreen Fräßdorf

“Lost Beauty”: Fish thought extinct rediscovered after 20 years

When researchers examined an inconspicuous, shallow pond on the edge of a remote remnant forest in Bolivia in spring 2024, they had no idea that right there—beneath leaves, gray mud and surrounded by vast agricultural land—they would find a species many already believed to be extinct: Moema claudiae, a seasonal

Lipochromis (Haplochromis) microdon Wiederentdeckung

Haplochromis microdon, an endemic cichlid from Lake Victoria, was considered lost for decades. The species can reach a length of up to 14.8 cm and is one of the specialized fish fry predators in the lake's ecosystem. (© Dr. Anna Mahulu, Institute of Ecology and Evolution, University of Bern)

11. May 2025 Doreen Fräßdorf

Lost in Lake Victoria: Cichlid Haplochromis microdon rediscovered after 40 years

For decades, it was considered lost—perhaps even extinct. But now there is new hope for Haplochromis microdon, an endemic cichlid species from Lake Victoria: As reported by the organization SHOAL in an article by Anna Mahulu, the species was detected for the first time since 1985 during targeted research expeditions

The first photograph of the snakehead fish Channa amphibeus. The species was already considered extinct after it had not been recorded since the early 20th century. (© Photo Credits: X/ @ranjeetnature)

1. February 2025 Doreen Fräßdorf

India: Lost Borna snakehead rediscovered after 85 years

The Borna snakehead Channa amphibeus, also known as the Chel snakehead, has been rediscovered in India’s Himalayan region. The species was regarded as one of the rarest and hardest-to-find snakehead species in the world, and scientists had already suspected that it was extinct. A research team led by Jayasimhan Praveenraj

Wiederentdeckung: Lachskarpfen (Aaptosyax grypus)

The photo shows giant salmon carp at a market in Laos in 1997. This predatory fish species living in the Mekong had been considered extinct since 2005, partly due to overfishing and habitat loss. (© Peter Cunningham, CC BY 3.0, via Wikimedia Commons)

29. December 2024 Doreen Fräßdorf

Mekong: Giant salmon carp, thought extinct since 2005, rediscovered

A study recently published in the journal Biological Conservation documents the rediscovery of the giant salmon carp (Aaptosyax grypus) in the Mekong river system. The species had been considered possibly extinct since 2005 because no confirmed records were available for a period of 15 years. Between 2020 and 2023, however,

Wiederentdeckung der Kurznasen-Maräne im Lake Superior (Oberer See)

It was here in Lake Superior that the shortnose cisco, believed extinct for 40 years, was surprisingly rediscovered recently. (© Yinan Chen, Public Domain, via Wikimedia Commons)

10. December 2024 Doreen Fräßdorf

Surprise find: The rediscovery of the shortnose cisco in Lake Superior

The shortnose cisco, a freshwater fish from the salmon family, had been considered extinct since 1985. After almost 40 years, it has now been rediscovered in a place where no one expected it: Lake Superior, the largest of North America’s five Great Lakes. Once, the shortnose cisco (Coregonus reighardi) was

At a body length of around 9.5 centimeters, the Abrau sprat is a relatively small fish. (© Лев Семёнович (Симонович) Берг (2 (14) марта 1876 — 24 декабря 1950), Public domain, via Wikimedia Commons)

3. September 2024 Doreen Fräßdorf

Russia: Believed-to-be-extinct Abrau Sprat Rediscovered

In October 2019, researchers collected nine small fish during an expedition from Lake Abrau in the Krasnodar region of western Russia. Recent DNA analyses have confirmed that the captured fish are indeed the endemic Abrau sprat (Clupeonella abrau), a species that had not been recorded since 2008. Challenges for the