Diamond-backed Watersnake

Nerodia rhombifer


The Diamond-backed Watersnake is a common, large species, found throughout the state in various swamps, lakes, rivers, ponds, and ditches. Labial scales are strongly barred. The body is usually green or olive colored with black blotching throughout. Juveniles may be much more colorful than adults. Belly usually blotched with black or brown checkering or half moons (see image below). Scales are strongly keeled, as they are in all Nerodia. Adults reach lengths of up to 4 feet, and beyond to 5 feet occasionally (Powell et al., 2016). This species is often mistaken for the venomous cottonmouth. This species nonvenomous. If confused, spending some concerted time learning venomous species will help. They primarily eat fish. 

Large male Diamond-backed Watersnake found stalking the shallow waters of a swamp, Iberville Par. (LA), © CJ Hillard

Identifying Traits

  • Dark blotching on¬†dorsum, olive or green body
  • Belly checkered with brown or black “half moons”


Bodies of water from rivers, to lakes, to swamps, to ditches


Highly aquatic, rarely seen far away from water bodies


Fish eater

N. rhombifer moving across a road, Issaquena Co. (MS)
Closeup of N. rhombifer, Issaquena Co. (MS)