Icelandic Plaice, like many of the flat fish species, has a dark topside and a white underside. It is normal for the fillets to reflect this in their natural colour once the skin is removed. The fish feed along the sea bed, mostly on mollouscs off the coast of Iceland.
Cook on stovetop or in the oven from defrosted. Fish is fully cooked when the fillet flakes with a fork. For pan frying, after about 2-3 minutes on one side, flip the fillet then finish off with an additional 1-2 minutes. Look for a golden-brown outer layer.