If you know how to get to PJ old town then you should be able to find your way to Old Klang Road. When you reach OKL,turn right and go straight until you see the police station and you wil see on the right there is a mosque. The road the mosque is on is Jln Puchong. Make your way to that road and drive straight down until you see a petrol station on your right,and there will be some flags with pics of koi with them. Turn in there and you will see Arowana Aquarium.