Tilapia has become a very popular fish in the US and now it is even known as "aquatic chicken" because it's relatively bland and breeds easily. Another thing it has in common with chicken is that it is being farmed and fed pellets of soy and corn which is a low cost way to fatten it up. The demand for tilapia has skyrocketed in the last ten years, due to it's low price and lack of a fishy taste.
The marketing campain behind tilapia encourages us to eat it for its health and environmental benefits, but this may not be true. Tilapia is quite low in beneficial Omega-3 fatty acids and when it's farmed it's even lower because it was fed corn and soy instead of its natural diet of aquatic plants and algae.
The environmental impact is potentially damaging to ecosystems due to breeding the fish which are packed into cages in natural lakes which then become contaminated with the waste. Another issue is that plenty of tilapia is coming frozen from China, whose farms have even less regulations. "Much of the fish that China exports is what producers call “refreshed,” which means it is frozen and packed in carbon monoxide to preserve color so it can be thawed and sold in fish displays, where it will appear to have been recently caught."
From a nutrition perspective, I'd suggest sticking to wild salmon, sardines, anchovies, and other oily fish that are rich in Omega-3 fatty acids. Even the Mayo Clinic is suggesting that farmed fish is not as heart healthy as wild caught varieties.
The Flip Side of Tilapia via the New York Times
photo: Katiek2 and Rose Robinson