Internal clocks can tick very differently. While some people are most productive in the morning, others are only active later in the day or at night. This phenomenon is known in science and medicine as chronotype. In a comprehensive analysis of the activity patterns of wild fish, a research team involving the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) has shown that fish – carp, trout, zander, and others – also have individual early and late risers. The results were published in the journal Fish and Fisheries.