If you ever wondered what to do with your leftover catfish guts, a Vietnamese innovator has come up with a dandy solution: catfish biodiesel. According to Reuters, a Vietnamese company called Agifish plans to turn catfish fat into fuel to run diesel engines. "The fuel is as good as diesel oil," said Agifish director Nguyen Dinh Huan who added that the company has been using the fuel, made from fat leftovers, to run pumps at its fish ponds in the Mekong Delta province of An Giang in southern Vietnam. We are not sure if this idea would be popular on Animal Farm (fish fat running a fish farm!), and it's not quite vegan, but the company claims that a kilogram of catfish fat could produce 1.13 litres of biofuel. Agifish plans on building a 10,000-tonne-per-year factory in 2007 to mass-produce the fuel for domestic markets. If it's using what would otherwise be considered waste, why not? ::New Scientist via ::Reuters.