This recipe can be prepared in 45 minutes or less.
Coarsely chop garlic and in a blender purée with tahini, water, lemon juice, cumin, and salt until smooth.
Using the flat side of a large knife coarsely crush coriander seeds. Pat catfish dry and season with salt and pepper. In a 10-inch nonstick skillet heat oil over moderately high heat until hot but not smoking and sauté fish 2 minutes. Turn fish over, sprinkling crushed coriander around it, and sauté 2 minutes more, or until just cooked through.
Divide tahini sauce between 2 plates and top with fish, crushed coriander and oil from skillet, and parsley.