The Rhône streber, a small fish that only France has

Those who love freshwater fish rarely know the Rhône streber, and that is exactly what made me want to read this article. Zingel asper seldom exceeds 20 centimeters, lives an average of three to four years, and spends the day motionless, pressed against gravel bottoms, before hunting insects and their larvae at dusk.

Its status is striking: it is endemic to the Rhône basin and lives nowhere else on the planet. Since 1996, the International Union for Conservation of Nature has listed it as critically endangered. Its range shrank from roughly 2,200 km of waterways at the start of the 20th century to only 240 km around 2010-2012, a loss of about 90%.

The article points to three causes: dams and artificial channels that fragment populations and erode their genetic diversity, water pollution from fertilizers and chemical residues, and warming water, even though the species prefers fast, well-oxygenated currents. Two national action plans, in 2011 and 2012, enabled the reintroduction of 22,000 fry into the Drôme, among other things. It can still be found in the Loue, the Ardèche, the Drôme, the Durance and the Buëch.

For a community passionate about aquarium keeping, I think it's worth remembering that the health of fish starts with the health of rivers. A fish that demands cool, clean, oxygen-rich water tells us a lot about what we should watch for in our own tanks.

Source: Sciencepost