Are there any kinds of fish you should avoid?

Some fish, such as tilapia and catfish, don't appear to be as heart healthy because they contain higher levels of unhealthy fatty acids. Keep in mind that any fish can be unhealthy depending on how it's prepared. For example, broiling or baking fish is a healthier option than is deep-frying.

Some researchers are also concerned about eating fish produced on farms as opposed to wild-caught fish. Researchers think antibiotics, pesticides and other chemicals used in raising farmed fish may cause harmful effects to people who eat the fish. However, some farmed fish — salmon, sea bass and trout — have higher levels of omega-3 fatty acids than their wild counterparts.