The Collaborative International Dictionary of English v.0.48:

Shanny \Shan"ny\, n.; pl. Shannies. [Etymol. uncertain.]
   (Zool.)
   The European smooth blenny (Blennius pholis). It is
   olive-green with irregular black spots, and without
   appendages on the head.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Blennius pholis
    n 1: European scaleless blenny [syn: shanny, Blennius
         pholis]