Text and photos by TMNCPC member Diane Eismont (from November Courier newsletter article.)
One evening about 6:45 p.m., I was going by our 300-gallon water tank when I saw a snake, about 18 inches long, swimming. It was the first time I had seen a snake in the water tank.
The tank contains plants and lots of Mosquito fish (Gambusia) in it. I threw some fish food into the water, attracting the fish over to eat it. The snake immediately followed and tried to catch a fish.
I have since read that these snakes swim in a figure-eight pattern with their mouths open to catch fish. I did see it catch and swallow a fish after repeated tries. These snakes are said to be primarily nocturnal, common, and vigorous biters if cornered.
Diamondback water snakes are nonvenomous and not to be confused with the Diamondback rattlesnake or Western Cottonmouth.
The diamondback water snake (Nerodia rhombifer) is predominantly brown, dark brown, or dark olive green with a black net-like pattern along the back with spots being vaguely diamond-shaped. The underside is generally a yellow or lighter brown color, often with black blotching. The adults are heavily bodied and usually about 5 feet although they can grow to 8 feet long.
Editor’s note: Earlier this year, the spring 2020 TMNCPC class observed a diamondback water snake among the iris along the edge of Seabourne Lake in Rosenberg.