is it common for crayfish to die when molding.
1 The process is called molting. 2  A crayfish reaches adult size in 3-4 months & its life span is 3-8 years long. 3  They grow old quickly. 4  The crayfish will either mate and start the process over again, or it will die. The process is called molting. 2  A crayfish reaches adult size in 3-4 months & its life span is 3-8 years long. 3  They grow old quickly. 4  The crayfish will either mate and start the process over again, or it will die.