Let the fish stand at room temperature while you are preparing the other ingredients. In a crock pot, combine the potatoes, carrots, parsley, bay leaf, tapioca, sugar, salt, basil, and pepper. Stir in the undrained tomatoes, chicken broth, tomato sauce, and sherry.
Halve the frozen block of fish crosswise; place the halves in the cooker. Cover and cook on a low heat setting for 10-12 hours or on a high heat setting for 3-4 hours. Remove the bay leaf. Break the fish into bite size chunks with a fork.