Aquatic Garter Snake

Thamnophis atratus

The aquatic garter snake (Thamnophis atratus) is a semi-aquatic garter snake of the western United States, especially California and southwestern Oregon. It lives along streams, ponds, marsh edges, and rocky pools where it can move quickly between water and cover. Color varies by population, but many have dark olive, brown, or blackish bodies with pale stripes or checkering. Like other garter snakes it bears live young, and it feeds largely on fish, tadpoles, frogs, salamanders, and other small aquatic or riparian animals.

Captive keeping is occasional and should start with local law, since collection rules and protected populations vary. A suitable setup needs both clean water and dry basking or hiding areas, tight lids, moderate temperatures, and frequent cleaning because fish-based diets foul water quickly. Keepers avoid relying on goldfish or other thiaminase-heavy feeder fish and often work toward safer whole-prey variety. In the wild, stewardship means protecting streamside vegetation, water quality, and seasonal pools from development, pollution, and nonnative predators.