The Goldfish Mistake: Why Garter Snakes Fail in the First 60 Days
Garter snakes get recommended to first-time keepers more than almost any other species, usually with the same pitch: hardy, small, native, and "they'll even eat fish, so feeding is easy." That last part is where a large share of new keepers go wrong. Because garter snakes really are natural fish-eaters, beginners reasonably default to a diet of feeder goldfish or minnows from the pet store — and within a matter of weeks, some of those snakes start showing head tremors, loss of balance, and a backward-arching neck that has nothing to do with a bad enclosure and everything to do with what's on the menu. A common garter snake (Thamnophis sirtalis). Photo: Brian Gratwicke, via Wikimedia Commons , licensed CC BY 2.0 . The one number: 25% of the diet Every figure in this guide hangs off a single threshold: 25%. That is the share of a reptile’s diet at which the Merck Veterinary Manual’s own feeding table stops treating frozen, thawed fish as a garnish and starts ca...