Huge water tank in the Underwater world in Sentosa island is amazing. There were more than 250 different species of 2500 marine animals in this the oldest and largest oceanarium in the region at that time. Here you can have a close encounters with sharks and stringrays. Stingrays flying towards you, dugongs, sharks and many other species of fish. The good thing is that fish cannot see what happens in the tunnel, as the glass is transparent only in the way from people to the fish.