How to Identify a Harmless Sea Mushroom Jellyfish

The harmless sea mushroom jellyfish, or the Rhizostoma octopus, can be found on the western and southern ocean shores of the British Isles any time of year. They are more often found along the beaches, however, in the summer months and in deeper water in the winter.

Difficulty:

Moderate

Instructions

1. Examine the coloring of the jellyfish. The harmless sea mushroom jellyfish can be an off-white color, a yellowish shade or light brown. It can also be light shades of pink, green or blue.

2. Study the shape of the jellyfish. If it is a solid-looking jellyfish with a dome-shaped bell that is thick in the middle and thin around the edges, the species very well could be a harmless sea mushroom jellyfish.

3. Assess the tentacles on the jellyfish. Harmless sea mushroom jellyfish have eight tentacles that are thick and long, which is why it is named "octopus." The top portion of the legs are covered with many mouths to catch particles in the water for food.

4. Look at the size of the jellyfish to identify it. The harmless sea mushroom jellyfish can grow to up to 39 inches in diameter.

5. Identify where the jellyfish is found. If the jellyfish is found in northwest Europe, it could be a harmless sea mushroom jellyfish.

Tips & Warnings

• There is nothing to fear from the harmless sea mushroom jellyfish. Its name says it all--it is completely harmless and does not sting.