Once the flatfish have been immobilized, they can be packed in a standard wet lock box lined with expandedpolystyreneorinoneofthenewstackableexpandedpolystyrenesystems. Inthesesystems, flatfishareplacedinshallowexpandedpolystyreneboxeswithdrainageholesinthebottom. Coolant is used in each of the boxes to maintain temperature. These boxes are then stacked (usually) three deep. The bottom box is a receiver for drip from the boxes above. Allowing for drainage helps to ensure that the flatfish are not packed in bacteria laden drip.