When bagging up fish, corals, or any type of marine aquarium livestock, it’s best to use more than one bag. Too many times we see things packed into single bags, which runs a very high risk of getting torn or punctured, spilling all of the water out and leaving your livestock to dry out. So, two bags should be a minimum, but don’t just put one bag inside of another, as there is another trick to it. Bag the livestock up with plenty of water and a large volume of air (preferably oxygen), then tie it off. After sealing up the bag, invert it and insert it into another bag. This will not only ensure the animals are safe, but inverting the inner bag will make sure that there are no corners that the animal can get trapped in. All that said, sometimes bags are suitable vessels for transporting certain livestock. Sea urchins, particular those of the longspine variety, tear up bags. They, and other animals that could cause bag damage, should be transported in a bucket or a hard plastic container when possible.