Fish

Question

Regarding buying fish in a supermarket, if the fish has already been flilleted, and is lying all day in a pile next to some shrimp , isn't there a concern that some of the non-kosher juices will be absorbed in the kosher fish. This is especially so since unlike a whole fish that you can just wash off (the skin prevents the juices from being absorbed) once it is filleted the juices can seep in, perhaps similar to the halakhah that a cooked meat with crevices that falls into milk absorbs the milk. Is this a problem, meaning that we should only buy fish that is filleted specially for us?