In a shallow bowl, beat the egg with the milk. Season the fillets with salt and pepper, then dredge the fillets in flour. Dip the fish in the egg wash and coat with corn flour. Heat the oil or butter in a large skillet, then fry the fish, over moderately high heat until crisp, about 4 to 5 minutes aside; blot on paper towels. Divide the fried tilapia between four serving plates and top each fillet with a poached egg. Spoon hollandaise sauce over the eggs and serve.