Fish stock for soups and chowders is simple. First fillet fish and set them aside for later. Remove head and tails, and place them in a 2gal pot of water. Add 1/2 tbsp salt, 6-8 whole allspice beads, chopped celery, parsley, onion.
Set to a low boil for 1-2 hours, or reduced to half of volume. Strain through a fine mesh sieve, cool, package and freeze.
Fish heads always make the best stock, as my Gram always said.