According to a recent report, a third of fish in the U. S.

 is being mislabeled, often dangerously.  For example, 

Tilefish should be called Feverfish, because it has

 more mercury in it than a thermometer; Snake 

Mackerel should be called Trotfish, because it 

gives you diarrhea; Silverfish, because its 

actually an insect; and Hagfish, because it's 

a rock-and-roll band from Dallas.