Small bodies of water, i.e., natural ponds, kettle holes and pools, account for 30 to 50% of the world's standing water. Owing to their size, however, the importance of small water bodies was long underestimated. As a result, they are scarcely mentioned in regulations and legal provisions. It is now known, however, that because of their abundance, heterogeneity, exceptional biodiversity and biogeochemical potency, small water bodies play an important role in catchments, landscapes, and possibly even on a continental scale that is completely out of proportion to their small size. On the occasion of World Water Day on 22 March, experts from the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) take a look with us at these rather under-appreciated ecosystems. Five answers to five questions: