I came across this jellyfish stranded on a beach in Wales. It grows up to 4cm in diameter and is recognised by its four purpley-blue reproductive rings. It has a smooth, saucer-shaped colourless bell.
It feeds on a wide variety of plankton, including fish eggs and small fish.
It is often found washed up on the shore. It swarms in coastal waters, bays and estuaries during April and September. It uses the sun as a compass, forming breeding aggregations in late summer following migration. Britain’s most common and widespread jellyfish.
Photograph taken June 2012, Llandudno, Wales.