Without knowing the actual species involved, tough to say for certain, but, if you have a well planted tank with multiple hiding spaces widely seperated for each crayfish, you should be able to keep 2-3. Given how agressive these guys are, you could still lose one if the dominate one isnt' willing to share territory or they aren't able to get completely out of sight of each other easily.Hi, I have a 55g tank with one juvenile electric blue crayfish. My questions are can I add another crayfish? How many? Can I add a white one? If so, will they mate? And what color will the babies be? Thank you for any info you can give me.