Grade A Green Texas Cichlid
The territorial Texas cichlid is the only cichlid native to the United States. Just like its Central American relatives, it can be quite aggressive and should only be kept by aquarists interested in dealing with belligerent fish.
The safest course of action is, of course, to keep the Texas cichlid on its own, but it can be combined with other hard-line species as long as the aquarium is at least 125 gallons. An aquarium of that size is also big enough to house a Texas cichlid pair, but be prepared to divide it into two sections if the couple turns out to be incompatible.