Sapphirina

Sapphirina, also called the sea sapphires, is a genus of parasitic copepod, containing the following species: Various species of male Sapphirina shine in different hues, from bright gold to deep blue. This is partially due to structural coloration in which microscopic layers of crystal plates inside their cells which are separated by minute distances, and these distances equal the same wavelength of the corresponding color of their 'shine'. The females are translucent, as are the males when they are not shining.