For sauce, add tea leaves into hot water and steep for 10 minutes. Strain the tea and add in the rest of ingredients. Mix well and bring mixture to a boil. Remove from heat and set aside.
Place ginger onto a plate and followed by fish fillets. Set aside.
Pour water and tea leaves into a wok, cover and bring to a boil. Turn down heat and simmer a further 5 minutes. Place in fish fillets and steam on high heat for 5-10 minutes or until fish fillets are cooked.Remove from heat and pour away residual liquid from the fish fillets.
Heat up the sauce if needed and pour over the fish fillets. Garnish and serve hot.