Quote Originally Posted by GradStudentLeper View Post
However I am also not convinced that thiaminase is a problem for fish eating snakes. They are not feeding on trout and salmon in the wild (Ok, T. atratus does), but rather on shad, minnows, etc. Fish that are high in thiaminase.
OK, so, I don't necessarily want to get all into this again, but it seemed worth making a small point... I used to think thiaminase was a problem only with frozen/stored fish, too, for all the reasons you stated. But there are quite a lot of studies on thiamine deficiency in wild salmonids feeding on alewives in the Great Lakes. (Alewives are invasive; the native fish that were the natural prey of the salmonids have low/no thiaminase.) So it does seem that a high enough thiaminase level can actually cause a problem for some predators even when consumed live. I don't think we know where typical feeders such as goldfish, rosy reds, shiners, etc. fall with respect to how *much* thiaminase they contain, so I think it's overly simplistic to say that there's "no problem" as long as the prey is live.

I do agree that a single high-thiaminase meal is unlikely to kill any garter that is otherwise on a varied and adequate diet. My baby Puget ate seven small rosy red minnows ten days ago and is perfectly fine, but he's also eaten guppies, silversides, and pinkies both before and since. But you'll never catch me recommending that to anyone directly, because I don't want their snake's death on my head if I'm wrong.