Source : Webster's Revised Unabridged Dictionary (1913)

Sheatfish \Sheat"fish`\, n. [Cf. dial. G. scheid, schaid,
   schaiden.] (Zo["o]l.)
   A European siluroid fish ({Silurus glanis}) allied to the
   cat-fishes. It is the largest fresh-water fish of Europe,
   sometimes becoming six feet or more in length. See
   {Siluroid}.

Siluroid \Si*lu"roid\, n. [Silurus + -oid.] (Zo["o]l.)
   Belonging to the Siluroidei, or Nematognathi, an order of
   fishes including numerous species, among which are the
   American catfishes and numerous allied fresh-water species of
   the Old World, as the sheatfish ({Silurus glanis}) of Europe.
   -- n. A siluroid fish.

Source : WordNet®

Silurus glanis
     n : large elongated catfish of central and eastern Europe [syn:
         {European catfish}, {sheatfish}]