Computers are changing very fast these days. Old computers quickly become out-of-date and are replaced by newer, butter ones. In the USA 200 million tonnes of old computers are thrown away each year. What to do with them all is a big problem. Carl Blake if Iowa, in the USA, has an unusual answer. He makes them into fish tanks He takes out the eletronic insides of the computers and fits a tank into the outer plastic shell. This is filled with water and becomes a home for a pet fish. You can watch your fish swimming through the screen. "It started as a joke", say Carl. But his company, MacAquarium, now produces around forty fish tanks a month. "We give the old computers another ten years of life", he say The tanks are very popular. Maybe fish are more interesting to look at than a real computer.