The best way to determine if a crawfish is alive or dead is by its movement. If the crawfish is moving, it is likely alive. If the crawfish is not moving, it is likely dead. Another way to tell if a crawfish is alive or dead is by coloration. A live crawfish will be bright red, while a dead crawfish will be duller in color. If you are still unsure if the crawfish is alive or dead, pinch it. A live crawfish will pinch back, while a dead one will not move.