It has significantly less omega-3s than wild-caught. I think it's primarily because of how they're "fed" by the farms, but I honestly don't recall 100% if that was it.

And no I don't worry about mercury, because I don't eat fish every day. Actually sometimes I don't eat seafood for a whole week or two, then maybe just two or three times the next week. Also, seafood is almost always my side item, I rarely eat large portions.