Siquia behavior is pretty typical of convict types, although I've seen some of the collection location variants be more aggressive than others. My male siquia from Rio Cabayo is the meanest "little" fish I've ever kept. He's rather large for a convict, probably around the 5-6" mark at this point, but is intolerant of any other fish in his tank. He killed at least 4 other fish before moving him to a permanently divided tank with the female on the other side of the divider. They spawn occasionally through the divider.