KRYPTOPTERUS VITREOLUS, freshwater fish native to Southeast Asia and commonly known as the “glass catfish” or “ghost catfish” because of its entirely transparent body. K. vitreolus is found in the Mekong and Chao Phraya River basins of peninsular and southeastern Thailand. Its scientific name refers to the two most salient aspects of its appearance: Kryptopterus means “hidden fin” in ancient Greek and refers to its absent dorsal fin; vitreolus derives from the diminutive form of the Latin adjective vitreus, meaning “of glass.”
K. vitreolus’ skin lacks not only scales (a trait shared by all catfish) but pigmentation as well, rendering its skeleton and internal organs visible. Even its barbels—the “whiskers” that give catfish their name—are transparent. After death the body of K. vitreolus takes on a milky-white color, leading researchers to suspect that some hitherto unknown active bodily process is responsible for its seeming cloak of invisibility.