Here's a link I found on a persons experience http://www.anapsid.org/crayfish.html
Not critical. Freshwater, but can tolerate a wide range of conditions. Cool, hard, alkaline, well aerated water is best for most species.
A temperature range of 65-77 F (18-25 C) is best for good growth of most species from the continental United States, but they can survive over a much wider range. Some species are tropical, some require cold water.
If the water is too soft or the pH is too low then there is a risk of calcium deficiency that could inhibit molting. Medium hard or hard water with a slightly alkaline pH, 7.5 - 8.5, is best.
They are normally 100% aquatic, but they can survive out of the water as long as their gills remain wet. They do not need to leave the water. The tank should be covered to prevent them from climbing out and going exploring around the house. They can climb up between the tank wall and a under-gravel lift tube, or climb up plants or a heater.
Omnivorous-fish, shrimp, meat, vegetables (frozen peas, boiled zucchini, carrots, etc.), sinking pellets, table scraps. Don't feed too much fat. Adults do not need a lot of protein, and should be fed primarily vegetables. I feed mostly frozen peas, some Tetra Tabimin pellets, carrots, and they catch the occasional fish. They also like the crickets that drown in my toad tank (the toads won't eat dead crickets).
Since they like vegetables they will eat many plants. They will devour plants that nothing else will eat, like Java Moss. They will uproot the plants they don't eat. I have lots of floating Hornwort (Ceratophyllum demersum) in my tank. They don't eat that too fast (it grows fast), and they like the cover above them.
Nocturnal. They like to hide during the day and need hiding places. Pieces of PVC pipe, rocks, driftwood, etc., can be used. They are cannibalistic if they are crowded or not provided with suitable shelter and lots of food. They can pinch HARD, so be careful.
Compatibility with fish
Crayfish will try very hard to eat your fish. They will lay in wait until a fish swims through their open claws, or if they have their tail curled up they can lunge forward a few inches to try to catch a fish. They may climb up plants to go fishing near the surface. I've seen them watch food that is put into the tank from a few inches away, and wait for fish to start eating it. Then they lunge forward to try to catch one.
I now have a single crayfish in a 10 gallon tank with White Cloud Minnows, feeder guppies, and a Chinese Algae Eater. The crayfish ate some of the guppies but the survivors are keeping out of reach. She ate all of my Zebra Danios, and half of my White Clouds. The Chinese Algae Eater is much too fast for her, and it even hides with the crayfish and sucks on her back. I'd recommend feeder guppies, feeder goldfish, or minnows from a bait store (anything cheap).
In the past I kept a crayfish with common (feeder) goldfish, and the crayfish was not able to successfully compete for food against the goldfish. I had to "hand" feed it with a pair of tongs. One day I came home and the four goldfish (about 3" each without the tail) had eaten about half of the 4" crayfish, and they had it well cleaned up by the next morning. I've also seen small goldfish get caught and eaten within a few minutes. Do not keep a crayfish with a fancy goldfish or any fish that is slow moving or has long fins. Do not keep them with Weather Loaches (Dojos), as they will lay on the bottom of the tank and allow the crayfish to walk up and pinch them."