Clownfish shrink during marine heatwaves – new study

Clownfish that shrank during heatwaves were more likely to survive them. Morgan Bennett-Smith

As the world contemplates dealing with more extreme temperatures, one coral reef fish has found a novel way to beat the heat: shrinking.

Wanting to know how clownfish cope with changes to their environment, we repeatedly measured 134 wild fish in Kimbe Bay, Papua New Guinea, during a marine heatwave that started in March 2023 and is part of an ongoing global mass coral bleaching event. Clownfish have unique markings, which make it easy to identify and measure them underwater.