Arizona requires an Aquatic Wildlife Stocking Permit (no fee) for any and all species. The G&F Dept. will then decide what fish they will allow. I was told that Tilapia are only permitted in Maricopa County (even though Blue Tilapia are already in Lake Mead in Mohave County) and that they may do a site inspection for access to waterways, flood control channels, etc. The way around this would be to file for a commercial aquaculture license through the Dept of Agriculture. This is very expensive and probably not worth all the goverment interference. I'm going with bluegill which will handle the winters here better anyway.