That's another reason that I feed my tilapia so little commercial feed, and instead raise them primarily on algae and greens, with other garden vegetables thrown in as treats (they frickin' love butternut squash and pumpkins).

Commercial tilapia farmers who raise their fish on commercial feed end up with fish that have a terrible omega3-to-omega6 ratio, it's roughly akin to bacon. It's easy to see why: commercial feed is largely corn (and gmo corn at that). If you raise your fish on corn, you're going to concentrate some bad things (like omega6) and fail to promote good things (like omega3).

When you raise tilapia on a diet of primarily algae and greens, you avoid the problem and end up with healthy meat that has a drastically better omega3-to-omega6 ratio.

I generally recommend that people not eat farmed tilapia from the grocery stores (most of which was grown in the Far East in very subpar conditions with subpar commercial feeds, frozen, and shipped here). Homegrown is a different story, though, if you keep and feed them right.