A tiny fish made this circle in the sand

Near Japan’s Amami islands, male white-spotted pufferfish create detailed circles in the sand. They’re tiny compared with their work: a fish roughly the length of your hand can shape a pattern around two metres wide. The grooves, peaks and finely worked centre do more than look good. Researchers describe them as a courtship and spawning structure, built with repeated movements of fins and body. It is tempting to imagine one perfect drawing appearing overnight. The real story is better: patient, repeated actions build the design, and it may need to be remade. These sand circles are built through repeated, careful movements rather than one dramatic sweep. Their delicate shapes are part of an underwater courtship, not permanent sculptures.