Fryeria rueppelii seems endemic to the Red Sea. It is recognizable according to following characteristics :
- the mantle is black with tubercles and it is bordered with yellowish orange
- the tubercles are bluish at the base and yellowish orange at the tip. The base of each tubercle is encircled by a bluish ring, which makes the tubercles look bell-shaped
- the rhinophores are yellowish orange

The genus Fryeria can be recognized according to the position of anus, located under the mantle, while it is located in the dorsal midline in other phyllidiids.

Fryeria rueppelii can be mistaken for Fryeria guamensis, Fryeria marindica, Fryeria menindie, Phyllidia coelestis and Phyllidia varicosa. They can be distinguished by the fact that Fryeria rueppelii is the only one having a yellowish orange border to the mantle.

Red Sea