The Halimeda tuna is a green marine algae of the Halimedacae family.
It appears as a chain of “round leaves” joined; it is fixed to the rocky substratum with thin rhizoids.
The color is green or yellowish-green, sometimes whitish due to the presence of limescale deposits.
It is present throughout the Mediterranean Sea but also in the Atlantic Ocean, the Pacific Ocean and the Indian Ocean. It is a typical algae of the coralligenous environment that tolerates light at low intensity, but it is possible to observe it even a few meters deep.