1. Recent studies have found that farm-raised tilapia may cause more inflammation.
2. Farm-raised salmon may have at least 10 times the amount of cancer causing organic pollutants compared to the wild variety.
3. Farm-bred fish also have lower levels of healthy nutrients.
4. Dibutylin levels, a chemical used in PVC plastics is said to be 6 times higher in farm-raised mussels compared to wild ones.
5. Farm-bred fish have been found to have high concentrations of antibiotics and pesticides.
6. Dioxin levels are 11 times higher in farm-bred salmon compared to wild salmon.

Source: http://www.draxe.com/eating-tilapia-is-worse-than-eating-bacon/