A US Food and Drug administration study once found that up to a third of all fish sold in the US is mislabeled and is actually a cheaper catch. Spotting mislabeled fish is essentially impossible—DNA tests are needed—but that could soon be changing with the help of a little device. A couple of scientists in Florida have come up with a fist-sized device that will tell you if a fish are grouper, or a less expensive Asian catfish. While the device only works for one type of fish, it is a step in the right direction to ending the sales of mislabeled foods. The device costs about $2,000.