Q: Got a great deal on a blue lobster, (I thing they are actually large crayfish right?), he is about 3-4 inches long and I am wondering if he will be fine with my Yellow Labs and Auratus?  I have lot of hiding places in my tank and lots of medium substrate to hide in.

A:   This is a bad idea.  Your "Blue Lobster" (crayfish) will have to repeatedly molt his shell and while this occurs his new shell is very soft making him vulnerable to cichlid attack.  Many hobbyists have attempted this combination and have not been able to make it work long term.  Even when a home is made for the crayfish small enough keep the cichlids out they always seem to eventually kill and eat it.   In the mean time, crayfish are nocturnal hunters and you may find half a fish occasionally in your tank when the crayfish gets lucky.