Gobioides broussonnetii - is a brackish water fish that prefers to live in estuaries and muddy bays. though some references will tell you it can acclimate to freshwater, my experience suggests that they do far better in brackish water. they can grow to two feet, ... prepare to trade him up to a LARGE tank. as far as feeding, the violet goby is a peaceful scavenger, and if well fed, should not bother smaller fish. they can and will however, inflict severe wounds with sharp teeth on other fish if 'annoyed'. i'd avoid keeping other bottom feeders in the same tank, especially slow movers like kuhli loaches since you may get to witness the wounds i've mentioned.