Mercury in Tilapia - most sources on the Internet show tilapia to be low 
  in mercury.  Dr Mercola states "So here is my list of safe fish:

     Summer Flounder
     Wild Pacific Salmon
     Croaker
     Sardines
     Haddock
     Tilapia"  http://www.mercola.com/2001/apr/25/mercury_fish.htm

Also "Lowest

     * salmon
     * flounder
     * sole
     * tilapia
     * trout
Source: Mercury levels in seafood species. U.S. Food and Drug 
Administration, Center for Food Safety and Applied Nutrition. Office of 
Seafood, May 2001."

So I'm not sure where you are getting your facts from.

Also tilapia are easy to raise if you are in a state that allows you to 
import and raise them.  They are easy to propagate as they will 
willingly make babies when the water gets warm enough.  I managed a 
solar green house at the Museum of Science in Boston for a year in 1987 
or so.  We had two circular tanks raising tilapia.  They can gulp air at 
the surface if the oxygen layers get too low, so if your air bubblers 
pumps quit they can survive until you find this out.  I had a whole tank 
of catfish die on me the day before Christmas when the air pumps to 
their tank went out.  You could easily raise a batch of tilapia to 
edible size and have a batch of babies to winter over until the water 
would be warm enough to start all over again. We fed them lettuce 
clippings and fish chow but there might be a less expensive way to feed 
them.

I enjoy eating tilapia.  I will cook it with either a salad dressing 
marinade or a coating of mayonnaise and Parmesan cheese on it.

Christy