Americans love their sushi.
The delicacy can be very expensive, as much as $200 per person for a meal at top sushi restaurants.
But how do you know when you order sushi, you're getting what you paid for and not a cheaper substitute?
To find out, INSIDE EDITION's I-Squad ordered sushi at 25 sushi restaurants in New York City and Los Angeles, from famous celebrity restaurants to local neighborhood hot spots.
The sushi was then wrapped up and we and shipped it off to a lab for some DNA testing
The results were troubling: 68 percent of the samples turned out to be a different fish than we ordered - often a cheaper variety.
In New York City, every time we ordered white tuna from the menu, we got something entirely different. It was usually a fish called escolar, which is sometimes referred to as the "Ex-Lax Fish" because it can be hard to digest and cause intestinal problems. Escolar is banned in Japan and Italy, but is legal in the U.S.
At Ariyoshi restaurant in New York City, white tuna was ordered but we were given escolar instead.
"Why would you switch one kind of fish for another kind of fish?" INSIDE EDITION's Lisa Guerrero asked a manager at the restaurant.
"Switch, no we didn't," he said.
He then brought out his shipping order to prove it but when we took a look, we saw the word "escolar" was printed on the order.
The manager then asked the I-Squad to stop videotaping the exchange.
Tamara Feuman, a registered dietitian, says she's seen some patients who have gotten sick after eating escolar.
"It's pretty awful. There's diarrhea, there's cramping, some patients will have some nausea and vomiting and it can last a day , a day-and-a-half, sometimes two days," she said.
Sixty percent of the red snapper we ordered turned out to be substituted as well, mostly with tilapia -- a much cheaper, farmed fish.
As for world famous NOBU, the fish we ordered is the fish we received.
So what can sushi-lovers do? Tamara Feuman has this advice: "Don't avoid sushi. Just make sure you order things that are a little clearer in what they are. Salmon, shrimp, things that are a little harder to fudge."