In the centre of the shop, as the crowd streams by, an albino fish in a glass tank has caught everyone’s eye. People cast longing glances as it sways gracefully, its metallic scales glinting in the afternoon sun. The arowana is the most expensive aquarium fish in the world, whose effusive tranquillity can set you back by a few lakh rupees. For many, particularly the Chinese, it is a harbinger of good luck.A ferocious predator, the arowana has survived since the age of the dinosaurs. Yet today i