A photographer’s strobe gives a violet sheen to this translucent juvenile roundbelly cowfish off the coast of Kona, Hawaii. Also known as the transparent boxfish, the roundbelly cowfish has two short horns in front of its eyes.

A copepod, a type of zooplankton, drifts in the Weddell Sea near Antarctica. Copepods are microscopic relatives of shrimp and lobsters

A pelagic, or open-ocean, octopus gives off a neon glow in Hawaii. Most species of octopus have no internal skeleton, unlike other cephalopods.

Antarctic krill, such as this specimen in the Weddell Sea with a stomach full of yellow algae, are a critical link in the ocean food web.

Lacking any other defense, many larval fish have adapted transparency as a method of camouflage—such as this tiny, see-through larval leaf scorpionfish in Hawaii.

A tiny jellyfish, with tentacles folded and its orange central mass visible through its transparent body, drifts in the waters of Antarctica’s Weddell Sea.

A transparent larval shrimp piggybacks on an equally see-through jellyfish in the waters around Hawaii.

An opalescent squid uses its giant eyes to navigate the nighttime waters around Papua New Guinea.

* Source: National Geographic