A glass octopus (Vitreledonella richardi) (Credit: Solvin Zankl/NPL)

A La Palma glass frog (Hyalinobatrachium valerioi) with its eggs (Credit: Ingo Arndt/NPL)

A swarm of moon jellyfish (Aurelia aurita) (Credit: Nick Garbutt/NPL)

Cyanogaster noctivaga has a translucent body (Credit: The Natural History Museum, London)

A sea walnut (Mnemiopsis leidyi) (Credit: Andrew Nekrasov/Alamy)

A pair of glasswing butterflies (Greta oto) (Credit: Edwin Giesbers/NPL)

A Venus' flower basket (Euplectella aspergillum) (Credit: Kim Taylor/NPL)

Clio pyramidata, a sea butterfly (Credit: Ingo Arndt/NPL)

Palaemonetes antennarius, a glass shrimp (Credit: blickwinkel/Alamy)

A blackfin icefish (Chaenocephalus aceratus) (Credit: Doug Allan/NPL)