Both of mine just look at me like I've offended them if I offer a prawn. I thought cats found them irresistible. MCat goes mental for tuna though. Little Monsieur's just not very food orientated full stop, even though he's not underweight or anything. When he was a kitten though, he'd steal anything that might bear the slightest resemblance to a food group.
Cats are fussy buggers though.