1. Transparent Amazonian FishCyanogaster, a recently discovered translucent fish.Photograph courtesy Natural History MuseumPlease be respectful of copyright. Unauthorized use is prohibited.

It’s speculated that the combination of its nearly invisible nature and nocturnal ways may be the reason why Cyanogaster noctivaga wasn’t discovered until now. The fish is also tiny, measuring an estimated maximum of 0.7 inches (17 millimeters) long and makes its home in the notoriously murky Rio Negro, which may have contributed to its elusiveness.

Being that hard to see confers obvious survival benefits as a form of camouflage, so it’s not surprising that when it comes to transparency it *ahem* clearly isn’t alone.

(See Photos of a Fish With a Transparent Head)

2. Golden Tortoise BeetleGolden tortoise beetles can shine metallic gold or change color to red.Photograph by George Grall, National GeographicPlease be respectful of copyright. Unauthorized use is prohibited.

The golden tortoise beetle (Charidotella 𝑠e𝑥punctata) is high in the running for the tiniest and most beguiling of nature’s translucent creatures. At 0.2 to 0.3 inches (5 to 8 millimeters) long it resembles a metallic ladybug and is something of a chameleon, shifting in color from gold to a reddish bronze throughout the year.

Also known as the “goldbug,” the lovely leaf-eater manages this transformation by reflecting light through liquid stored below a transparent outer cuticle.

3. Glass FrogsThe translucent glass frog Hyalinobatrachium pellucidum.Photograph by Joel Sartore, National GeographicPlease be respectful of copyright. Unauthorized use is prohibited.

Hyalinobatrachium pellucidum, also known as the “glass frog,” is native to the cloud forests and rivers of Ecuador. Hyalinobatrachium pellucidum’s pale green skin is translucent to the point that the majority of its vital organs are clearly visible. Unfortunately, the species is endangered due to continuing habitat destruction.

4. Sea AngelsA sea butterflyfish swims in waters off Enderbury Island.Photograph by Brian Skerry, National GeographicPlease be respectful of copyright. Unauthorized use is prohibited.

Sea angels are mollusks native to the Arctic Ocean whose scientific name Gymnosomata is Greek for “naked body” and whose appearance is both ghostly and beautiful (see video below). Sea angels are hermaphroditic and feed on another, possibly related, species of “winged” mollusk known as the sea butterfly (Thecosomata). Since they appear to flutter through the water on tiny translucent wings it’s easy to see how sea angels got their common name, although they also have pointy protrusions that resemble horns…

Barton Springs SalamanderAn endangered Barton Springs salamander, Eurycea sosorum.Photograph by Joel Sartore, National GeographicPlease be respectful of copyright. Unauthorized use is prohibited.

The Barton Springs salamander (Eurycea sosorum) is a small lungless salamander unique to Barton Springs, a group of natural springs in Austin, Texas. Its speckled, reddish-brown skin is translucent and eggs or even the contents of the salamander’s last meal are often visible.

Since the Barton Springs salamander is found nowhere else in the world and relies on fresh, unpolluted spring water it’s been listed as an endangered species since 1997.

While for many animals translucency is a way of life, some creatures exhibit it only in certain phases…

Translucent TadpolesNote the tadpoles’ coiled intestines.Photograph by Paul A. Zahl, National GeographicPlease be respectful of copyright. Unauthorized use is prohibited.

These Costa Rican tadpoles have see-through skin that reveals neatly coiled intestines.

Larval SquidA transparent larval squid.Photography by David Liittschwager, National GeographicPlease be respectful of copyright. Unauthorized use is prohibited.

This larval squid shows off translucency and iridescence in equal measure.

Monarch Butterfly PupaA translucent monarch butterfly pupa.Photograph by Paul A. Zahl, National GeographicPlease be respectful of copyright. Unauthorized use is prohibited.

This monarch butterfly, seen at a tender age, offers a preview of its famous brilliant orange hue peeking out from the transparent coating of its pupa.