Think you know exactly what fish you’re eating when you order sushi? Think again.

The ocean conservation group Oceana found through DNA testing that one-third of the nation’s seafood is mislabeled, according to U.S. Food and Drug Administration (FDA) guidelines.

From 2010 to 2012, researchers from the group gathered 1,215 seafood samples from 674 retail outlets in 21 states. Of the samples, 33 percent were labeled inaccurately.

Products sold as snapper and tuna were mislabeled at the highest rates – 87 percent and 59 percent, respectively. Of the 120 samples of “red snapper” tested in the study, only seven were actually red snapper, while the other 113 samples were another fish entirely.