"where the money is" is going to depend on where you are... friendlies is in HI, all kinds of fresh seafood available..
tilapia is really cheap around here in ohio (3.99/lb) and is to costly to grow in our climate because of heating.. yellow perch on the other hand, sells for 14.99/lb regularly..
each "commercial" operation has to find it's own market..
on "another" forum, i've been following the documentation of a commercial build in minnesota
nelson and pade have done some stuff in the states, but info is kind of hard to find