Hi there.
Just to give you an introduction between Australian and American species:
<Marrons>
Cherax Tenuimanus - Hairy Marron - Thin Chelipeds
Cherax Cainii - Smooth Marron - Broad Chelipeds
<Procambarus Species>
Clarkii - Rugged edges along the carapace - Your common red crayfish, although there are blue moults, most of the blue American species found are actually Clarkii...
Alleni - Smooth edges along the carapace - Your real Electric Blue Crayfish aka Blue Florida Cray