Painted Top Shell Nudibranch

This striking yellow-and-black nudibranch is among the most common aeolid species found on Icelandic lava walls, feeding on encrusting bryozoans that colonise the basalt. It is active year-round even in near-freezing water, demonstrating the cold-water adaptations common to Nordic nudibranchs. Dense colonies of its preferred bryozoan prey make the Dalvík Wall a reliable sighting location.