- Kingdom: Animalia
- Phylum: Cnidaria
- Class: Scyphozoa
- Order: Semaeostomaeida
- Family: Ulmaridae
- Scientific name: Aurelia aurita
- Norwegian: glassmanet
The umbrella is flat and with a diameter usually ranging from 25 to 40 cm. There are usually four, but sometimes none or as many as 7 or 8 horseshoe-shaped gonads. These are very conspicuous, due to the color (red, pink, magenta or blue) and the transparent bell.
The moon jelly feeds on plankton that sticks to its surface. During late fall or early winter it disintegrate, as many other jellyfish. The offspring survives the winter as larvae attached to the bottom. By asexual reproduction it forms stacks of platters which are released in the spring to start their medusa phase.
It is usually found close to the surface, but may go deep under harsh weather conditions.
This is a cosmopolitan found in northern boreal as well as tropical water. It is the most common jellyfish in the North Sea.