Wrap the tofu in a clean towel to drain.
Break up the dried mushrooms and soak them in the cup of water.
Slice the fish into bite sized pieces.
Cut the tofu into bite sized pieces. If you choose, heat oil in a pan, and brown the tofu until golden. Remove and reserve.
Heat the mushrooms and their liquid, and the chicken stock, in the pan. Add soy sauce and ginger. When the liquid comes to a boil, add the frozen vegetables. As soon as they are heated, add the scallions, tofu, and fish. Keep at a low simmer until fish is cooked. (3-5 minutes - watch carefully that it doesn't overcook.)