Glass catfish

This is a transparent freshwater catfish with two long barbels. Standard lengths may range up to 8 cm (3.1 in), but usually only reach around 6.5 cm (2.6 in) in total length. They are transparent because, like all catfish, they are scaleless, and catfish within the genus Kryptopterus lack body pigment. Most of their organs are located near the head; with a magnifying glass, their heart can be seen beating. When the light strikes the fish just right, it can create an iridescent rainbow color. During strong illness and after death, they turn milky white. The scientific species name vitreolus is derived from the Latin vitreus, which means glass. Among described species of Kryptopterus, only two other species, K. minor and K. piperatus, have clearly transparent bodies and both these are largely–if not entirely–absent from the aquarium trade. The body of others, including K. bicirrhis, are only somewhat translucent or opaque.