DuckCorp Dico

Found one definition

1.                 From The Free On-line Dictionary of Computing (19 January 2023):
                   
   
   
                   
                     
   fish
      (Adelaide University, Australia) 1. Another metasyntactic
    variable.  See foo.  Derived originally from the Monty
      Python skit in the middle of "The Meaning of Life" entitled
      "Find the Fish".
      2. <storage> microfiche.  A microfiche file cabinet may be
      referred to as a "fish tank".
      [Jargon File]
      (1994-12-01)