Glothr

The Glothr are a species of aquatic, jellyfish-like methanogens native to the intergalactic rogue planet Invictus. They are a highly advanced sentient species subordinate to the Sh'daar. They first appear in the sixth Star Carrier novel, Deep Time.

Anatomy & Physiology
Glothr resemble cylindrical jellyfish, with bodies about three meters in height. Their tentacles are rather short and do not add much to their overall height. They have twenty-four eyes arranged in three circles around their bodies, granting them 360-degree vision, and they are capable of using bioluminescence to illuminate their bodies in numerous colors.

Biochemistry
Glothr biochemistry works at extremely low temperatures. They breathe hydrogen instead of oxygen and use it to burn acetylene instead of glucose, exhaling methane instead of carbon dioxide. The low temperature and inefficiency of this process renders the Glothr metabolism very slow, to the point where they move, think, and act at rates considered glacial by most other species.

Diet
Glothr gain the energy and carbon they need by consuming acetylene. It is unclear if they ingest acetylene directly from the environment or from other organisms, but the novel's explanation of their biology implies the former; acetylene is contrasted with food rather than glucose.

Reproduction & Life Cycle
Glothr have four sexes, and change between them throughout their lives. Their young are non-sapient, and while the Glothr care for them to some degree they do not consider their deaths, even in great numbers, to be a serious loss. Glother presumably have very long lifespans due to their slow biological processes.

Senses
Glothr rely primarily on an electrical sense, using it to navigate and to communicate. Despite their extremely dark environment, they can also see, and use bioluminescence as part of their language.