Combine water and bonito; let stand 2 minutes. Strain the liquid through a fine sieve into a bowl; discard solids. Bring the liquid to a boil in a large saucepan. Add yellow and red miso and soy sauce; stir well with a whisk until smooth. Divide the enoki mushrooms and tofu evenly among 6 soup bowls, and ladle 1 cup soup into each bowl.