Whisk the orange juice, coriander, ginger, garlic, soy sauce, sesame oil and chilli flakes together in a small bowl; set aside.
Heat the olive oil in a frypan over medium-high heat. Cook the fillets until golden brown on each side, 2 to 3 minutes per side. Pour the orange juice mixture into the frypan and bring to a boil. Reduce heat to medium and simmer until the fish flakes easily with a fork and the sauce has thickened slightly. Remove fish to a plate and drizzle with orange sauce to serve.