If you need to hold them until later in the day it is best to keep them in their packaging and refrigerate them. If you cannot fit your cooler in the refrigerator, put your lobsters in a paper bag on a drip tray or dish to catch any water that may leak, and don't seal them in a plastic bag. Without proper salinity and temperature control the lobsters will die. The shade varies a little from lobster to lobster, but they are a dark blue-green when alive. The lobster's color is caused by pigments in the shell.
Cooked lobster is red in color.
When the lobster is cooked, all of the color pigments are masked except the red background color. If you ordered live lobsters, they will have been out of water for almost 24 hours when you receive them. Occasionally, one may appear weak or lifeless. This is a normal occurrence. In most cases, as long as the packaging material is in good condition, and the refrigerant is still cold, your lobsters will be fine.