Mermanite

The Mermanites are a sapient race of mermaid-like creatures that inhabit the Sea of Tranquility on the planet Sagar.

Biology
The Mermanites are sea-dwelling creatures with a humanoid upper body and an ichthyoid tail. They have greenish skin and pointed ears, and their tails are pale-green. Males are completely bald, while females possess dark green hair. Their diet includes fruits and nuts, which they acquire from land-based allies, like the Trobbits.

Culture and society
Mermanites wear golden bracelets and necklaces, and the adult females cover their breasts with sea shells. Children wear loose and softer necklaces and no bracelets. They're a peaceful people ruled by a queen, and are allies of the Trobbits and John Blackstar. The Mermanite queen is the only one that wears Human-like clothes, as well as a crown on her head, instead of a necklace.

Appearances

 * Blackstar, s01e04, "The Mermaid of Serpent Sea" (1981)