Fish stock forms the basis for seafood sauces, soups, seafood meals and more. This is a basic version with the addition of optional white wine. Make a big batch, then freeze it, ready to use. If you’re using flat style fish like sole, flounder etc then only cook it for 20 minutes otherwise you may get bitterness out of the bones. It’s also professionally know as Fish Fumet, or Fumet de poisson. Ask your fish monger for the freshest heads and bones you can get. If you’re a regular customer, chances they won’t even charge you. Never buy stock again.