Johannes or John Waterstradt was a German-born Danish natural history collector and mineral prospector in Southeast Asia. He collected birds, orchids, butterflies and moths from the Papua New Guinea and Indonesian regions for several European collectors including Otto Staudinger and Hans Fruhstorfer. The mountain peacock pheasant Polyplectron inopinatum was named and described by Walter Rothschild from a specimen collected by him. He was a pioneer of commercial orchid cultivation and hybridization in Denmark.