Creamy Seafood Noodles

Ingredients

1 large onion, chopped
4 cloves garlic, minced
1 cup fresh mushrooms, sliced
9 ounces fresh (raw) fish, cubed
9 ounces fresh (raw) prawns, peeled
3 cups water
2 3-ounce packets Oriental flavoured noodles
2 3-ounce packets shrimp flavoured noodles
2 tablespoons sour cream
9 ounces imitation crabmeat
salt and pepper to taste