fish stock doesn't take nearly as long to make as others (chicken, beef, etc.) imo. good all around additions are carrots, celery, onion, bay leaf. put all in a stock pot, cover with water, bring to a boil, turn down heat and simmer 30-60 minutes. strain throung cheesecloth or a fine wire mesh strainer. if not using within a couple days freeze. i find it nice to fill ice cube trays, then put the cubes in gallon freezer bags. makes it easier to use what you need than freezing large blocks, unless you are planning on making a large amount of stuff.