Chytrid
Also called: Chytridiomycosis · Bd
Chytrid (chytridiomycosis, caused by the fungus Bd) is a devastating amphibian skin disease that disrupts the skin's ability to breathe and balance salts, and is a major driver of amphibian extinctions worldwide.
It is why you never release a captive amphibian into the wild, never move animals or water between the wild and captivity, and quarantine new arrivals. A sick amphibian needs an exotics vet — chytrid is treatable in captivity but is a serious diagnosis.
It is also why responsible keeping matters for conservation: the pet trade can spread disease if animals are moved carelessly.