Have you kept a crayfish with other fish successfully?

Yes, first I have a tiger lobster that (crayfish) that I put in my piranha tank when they were really small. He did fine in there until they got bigger and then he was just hiding in the skull all day so I took him out and put him in my other tank with black mollies, odessa barbs, a swordtail, catfish and pleco. I also now have a Blue Crayfish in the same tank and so far no problems although I do see him try to grab a fish when they come to close but they are pretty fast and so far no fatalities! Both crayfish have molted too, quite interesting, seem to be growing and getting along with each other.