When we go out to a restaurant and peruse the menu, it’s a reasonable assumption that we’ll be served the dish that we order. Likewise, when we’re doing our grocery shopping, there’s no reason to believe that the products we buy are misrepresented. Until now, that is.

According to a report recently published in the New York Times, two ingenious teenagers elevated a science project to a whole new level, and in the process discovered that when New Yorkers order the fish, they might be getting the bait and switch.

Kate Stoeckle and Louisa Strauss trekked to sushi restaurants and grocery stores in New York City and collected samples of seafood. They then sent the samples to a lab in Canada that had agreed to genetically analyze the fish and compare them to a database of over 30,000 fish.

The result? According to the Times, “2 of the 4 restaurants and 6 of the 10 grocery stores had sold mislabeled fish.” The piece went on to say:

A piece of sushi sold as the luxury treat white tuna turned out to be Mozambique tilapia, a much cheaper fish that is often raised by farming. Roe supposedly from flying fish was actually from smelt. Seven of nine samples that were called red snapper were mislabeled, and they turned out to be anything from Atlantic cod to Acadian redfish, an endangered species.

The bottom line for consumers? Whether you’re spending tens of thousands of dollars for a car or $20 on a seafood dinner, you’re always better off if you learn about the product you’re buying so you’re less likely to get ripped off.