My only piece of advice to you, is don't get a crayfish if you plan on having other fish in the tank. I bought my crayfish because I wanted something that lives at the bottom, in my caves. As soon as I dropped the guy in, he started chasing my pleco. Once my pleco got away, he literally picked up the gold mystery snail with his claws, shook him back and forth over his head, and then threw him across the tank
I knew this wasn't going to turn out good, so I keep him in my 10 gal quarantine tank now. I've had him for about 8 months now, and even tried to get him another crayfish friend. He ate him. I keep my feeder goldfish in the same tank too, and if I buy 2 dozen, he'll probably eat about 4 or 5 of them.
Bottom line, he doesn't do well with others haha.
(Also, he uproots any plant he sees, and redecorates how he sees fit)