How this little see-through fish gets its rainbow shimmer

NEW YORK — You can see right through this little aquarium fish from Thailand: Its skin is almost completely transparent. But when the light hits it just right, its body flickers with shimmering rainbow colors.

Now, scientists have figured out how this fish — called the ghost catfish — creates its iridescent glow.

That glow comes from within, according to a study published Monday in the journal Proceedings of the National Academy of Sciences. As light passes through the fish’s skin, it hits tiny structures in the muscle that turn the light into a colorful spectrum.

The ghost catfish — sometimes known as the glass catfish — is a small species native to rivers in Thailand, averaging just a few inches (centimeters) long. It’s sold around the world as an…