The compass jellyfish is an easy one to spot with its 16 reddish-brown V shaped marks around the bell. The V shapes develop from a central point and resemble a compass. The edges of the bell develop into 32 lobes and have 24 marginal tentacles. They have four frilly oral arms which are longer than the marginal tentacles.

The marginal tentacles are covered in nematocysts (stinging cells) which they use for stunning their prey. Some young fish have been observed swimming around the compass jellyfish tentacles which they seem to be using for protection. This species feeds on small fish, crabs as well as other jellyfish. The compass jellyfish is a summer visitor to the Irish coastline but don’t get too close if you see one! They can give a nasty sting.