The Fish That’s Almost Completely Invisible What animal survives by making its entire body almost disappear? Meet the glass catfish — a freshwater fish so transparent you can see its bones, organs, and beating heart through its skin. Native to the rivers of Southeast Asia, the glass catfish lacks most of the pigments that normally make animals opaque. Light passes straight through its body, leaving only a faint silver outline and a visible spine suspended in water. To predators, it’s less a targ