Source : Webster's Revised Unabridged Dictionary (1913)

Fish-tail \Fish"-tail`\, a.
   Like the of a fish; acting, or producing something, like the
   tail of a fish.

   {Fish-tail burner}, a gas burner that gives a spreading flame
      shaped somewhat like the tail of a fish.

   {Fish-tail propeller} (Steamship), a propeller with a single
      blade that oscillates like the tail of a fish when
      swimming.