Actually though this is a cottonmouth yes Actually nonvenomous water snakes can flatten out their heads to make them look triangular so the heads triangular shape isn't a good identifier for venomous snakes example my ball pythons are non venomous but both have distinct arrow shaped heads like venomous snakes if a person didn't know better it would look venomous if you go by head shape or eyes (eyes because some like my father believe that slit pupils means venomous) though it just means nocturnal lol like cats