I have 2 at over a foot each, however only 1 of them is a G. broussoni(or whatever it is),. the other is a G. Peruanus. IO don't no if the G P is rare, but it is definantly rarer than the common G. broussoni. These fish have lage mouthes, but small throats, making them good with the smallest of fish. I have kept mine with a school of pea sized convict fry, no problems. do no keep them with fish that nip fins such as barbs. They will always come from amazon estuaries, and come in brackish aclimated. they can be acclimated to full fresh, but it must be done very slowly. you can through one from a fw tank into brackish, but not vice versa, or they will slowly die.