I think I might actually be allergic to seafood: eating cod or haddock sometimes makes me feel a little sick to the stomach, last time I had salmon I had diarrhoea the following morning, and yet while I've had sushi on a number of occasions, it's only made me sick once, and most likely because my stomach, already a bit sensitive to seafood, didn't seem to like me dropping a greasy doughnut on top of raw salmon :P

I don't eat seafood as much as I used to, but I probably should once I'm not living on student budget any more.