Deep-sea shrimp have organs called photophores, which emit this to help identify a mate
[DOC] [TLE] ORCA - Ocean Research and Conservation Association - Team & Staff [PAR] For example, the light emitting chemistry of fireflies has been extracted and used 
... light with a chemical reaction and though the substrate is called luciferin and 
the ... their light to help attract mates, others, like many of the shrimp and squid 
use .... the pattern of photophores (light-emitting organs) is often a key 
characteristic.