To survive as a species, aquatic organisms have developed a wide variety of strategies. Millions of years ago, sturgeons used their bony shells to fend off predators and relocate their habitats, sulphur mollies survive in toxic, almost oxygen-free water, and fish stocks in the River Oder are gradually recovering from the 2022 disaster. However, there are limits to the resilience of organisms, and these can be seen even in the tiniest single-celled creatures.