No. Fish can last a significant amount of time in these bags, dependent mostly on oxygen levels and the size and messyness of the fish. Fish are shipped in these bags to your LFS from the wholesaler. They are shipped overnight, but that means many fish are in their little bags for at most 24 hours. So long as the fish store adds some pure oxygen to the bag, the fish will do just fine. To regulate temperature, fish are often shipped in styrophome coolers with either heat pads or cold packs, depending on the temps where they are being shipped.
\Dan