Preheat oven to 300 degrees F (150
degrees C). Lightly grease a medium baking dish.
Melt butter in a medium saucepan
over medium heat, and stir in flour until smooth. Gradually stir
in chicken broth and sherry. Cook, stirring constantly, until
thick and bubbly. Mix in chives, basil, and thyme. Remove from
heat, and set aside.
In the prepared baking dish,
arrange the orange roughy fillets in a single layer. Season with
salt and pepper. Arrange tomato slices over the fish. Cover with
the broth mixture.
Bake 30 to 40 minutes in the
preheated oven, until fish is easily flaked with a fork.