Source : Webster's Revised Unabridged Dictionary (1913)

Numbfish \Numb"fish`\, n. (Zo["o]l.)
   The torpedo, which numbs by the electric shocks which it
   gives.

Source : WordNet®

numbfish
     n : any sluggish bottom-dwelling ray of the order
         Torpediniformes having a rounded body and electric organs
         on each side of the head capable of emitting strong
         electric discharges [syn: {electric ray}, {crampfish}, {torpedo}]
     [also: {numbfishes} (pl)]