Freshwater fish are the most endangered group of vertebrates on earth. Now, networks of home-based aquarists are trying to save some of the most threatened species, keeping them alive in basement aquariums in the hope they might someday be reintroduced into the wild.
Michael Koeck [center left] gives a tour of the 90 tanks he manages in the basement of the Haus des Meeres aquarium in Vienna. CREDIT: JUTTA KIRCHNER
In August 1940, just after the first-ever British bombing raid on Berlin in World War II, Hitler decided to construct colossal Flakturme
— fortified anti-aircraft towers, supporting gun batteries and radar dishes — in important cities of the Reich. Their walls were up to 3.5 meters thick, which is why Flakturm V-L in Vienna proved impossible to demolish after the war, and why we now know that the basement of a Nazi blockhouse is the perfect place to keep 90 glass tanks full of obscure Mexican fish.
“I’m a lazy aquarist,” says Michael Koeck, curator at the Haus des Meeres, the public aquarium that today occupies Flakturm V-L and houses the 90 basement tanks. In 1998, he says, he was in a tight spot. A keen ornamental fishkeeper, he had no suitable fish for his aquarium club’s upcoming show. “I was working in a pet shop and this guy came in and said, ‘I have some rare fish, do you want to buy some?’” Koeck immediately bought them to exhibit. “After the show, I recognized that I was not able to give the fish back. I had to keep them.”
“The fish” were two species of goodeids, a little-known family of tiny livebearers somewhat related to the common guppy. Native to Mexico, they proved easy to maintain. “They don’t need any heating, so I could give away my heaters,” says Koeck, and the chemistry of Viennese tap water suited them. They give birth to live young, obviating the need to cosset eggs and tiny fry. “They fit perfectly to my lifestyle, that’s why I kept them in the end, and it was only later I recognized they are endangered.” Koeck had unwittingly taken the first step toward becoming a key player in an off-mainstream global conservation effort, much of which literally plays out underground.
Freshwater fish are the most endangered group of backboned animals on the planet. Vulnerable to numerous threats including pollution, dams, mining, invasive species, and climate breakdown, they are largely ignored by big conservation groups and funders. Fish species often sink into extinction unnoticed and unnamed; a shortage of fish taxonomists means that thousands of types of fish that appear to be new species are not yet scientifically described.
At the same time, there are millions of hobby fishkeepers around the world and an industry to support them. Some hobby aquarists maintain tens or even hundreds of fish tanks, often in their basements because of weight and space constraints, and know more than academic experts about the animals they keep. A small but increasing number of these aquarists have reframed their hobby as a form of conservation and have self-organized into shoestring-budget international networks to share knowledge and fish — and to fight extinction on the home front.