Ring-eels are a species of 'thin atmosphere ring fauna', the evolution of which is still uncertain. They are the largest species of ring fauna, whose range encircles the planet Soruica from its innermost ring system practically to synchronous orbit with the planet.

The eels are observed mostly among the thin atmosphere trapped by Soruica's ring system, but may migrate out to distances of soruisynchronous orbit for as yet unknown reasons, although patterns are seen of this behavior occurring when an eel is searching for a new territory within the ring system, while allowing the rings to pass in faster orbit. This theory would require the extraordinary assumption that ring-eels can see features of the ring system from large distances.

Movement in very thin- to non-atmospheric conditions is facilitated by the eels by jets of molecular oxygen being expelled from vents in the sides and tail of the eel in various directions.

Eels prey on smaller fauna in and around the ring system by opening a large set of toothless jaws and propelling themselves in the direction of food, usually sendrils, which are easily chased or stranded out of atmosphere and unable to change direction.