The Collaborative International Dictionary of English v.0.48:

Id \Id\, n. (Zool.)
   A small fresh-water cyprinoid fish (Leuciscus idus or Idus
   idus) of Europe. A domesticated variety, colored like the
   goldfish, is called orfe in Germany.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Orf \Orf\, Orfe \Or"fe\, n. (Zool.)
   A bright-colored domesticated variety of the id. See Id.
   [1913 Webster]