Fried Egg Jelly

Overview

The Fried Egg Jelly (Cotylorhiza tuberculata) is a distinctive jellyfish native to the Mediterranean Sea, easily recognized by its unique appearance that resembles a sunny-side-up egg floating in the water. While they can form large, visually striking aggregations during the summer months, they are generally harmless to humans and pose little to no stinging risk to most people.

Appearance

This species features a smooth, translucent white bell with a prominent, elevated yellow-orange central dome that mimics an egg yolk. Below the bell, it possesses numerous short, club-shaped oral arms that often end in purple or white, disk-like appendages. Adults typically reach diameters between 15 and 40 cm.

Biology & behavior

These jellyfish are pelagic and often host small juvenile fish, which find shelter and protection among the jelly's tentacles. A fascinating aspect of their biology is their symbiotic relationship with zooxanthellae—tiny photosynthetic algae living within their tissues—which provide the jellyfish with additional energy. They are frequently observed in warm, calm coastal waters, where their presence is sometimes used as an indicator of broader ecological shifts in the region.