Since beginning MF, I bought a George Foreman grill. In the booklet that comes with the grill, it suggests cooking tilapia(3/4inches thick) for 5 minutes for well done, 4 min for medium, and 3 minutes for rare(oh, yuk!). Food really gets done very quickly on the Foreman, so it needs to be watched closely, especially when cooking fish. Hope this helps!
Also, if fish is really fresh, it shouldn't smell fishy, so they say. And, I guess this means that we all have to run to the docks, wait for the boats to come in, and then run home and cook it!! uh-no!