Imagine a pet fish that never needed feeding, and whose tank never needed cleaning. That’s what the Japanese have come up with – it’s surprisingly lifelike. Robofish, invented by Takara Tomy, even looks as if it is searching for and eating food, bobbing up and down on the floor of the tank. There appear to be several varieties, all powered by tiny batteries. You can buy them on Amazon Japan for about $37 – though anglers won’t learn a lot from their behaviour. Details here.