Thank you for your response Libor.   
      
   Just to be sure I was clear, the fish I display must be held at a temperature   
   betw. 0deg F and 40 deg F (and the closer to 0deg F the better), but   
   temperature of of the ice I already use to do that 'begin' at below 0deg F and   
   my walk-in freezer can cool    
   its contents to any setting betw -10deg F and 0deg F.   
      
   It occurs to me therefore that within certain sanitation limits (eg toxicity   
   and porosity ) I should consider freezing and using all sorts of ice   
   alternatives including any of the following in frozen form:   
   - glass marbles,   
   - blue ice packs,   
   - oyster shells,   
   - layers of plastic,   
   - certain food grade woods,   
   - beach toys,   
   - beach sand or beach stones,    
   - real or imitation coral,   
   - oyster shells,   
   - pirates' treasure,   
   - seaweed,   
   - bottles of rum,   
   - crab claws,   
   - aquarium ornaments,   
   - bottles of sunscreen containing anything in frozen form   
   - certain frozen foods (capers, coconut shavings, salt water taffy.)   
      
   Obviously, since I am trying to keep something cold I need something with a   
   high specific heat.   
      
   If I understand your response correctly, ultimately my choices will be limited   
   to water or things containing water, is that correct?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)