Reptile & Amphibian Forums

having unexpected trouble switching my litter of 2-month old NWS from live minnows, which they eat with gusto, to frozen/thawed. They seem to need the movement, but offering bits of thawed fish in front of them doesn't do it for them. Advice?

Tap them on the side with the piece of fish; I've found that most Nerodia respond to prey items brushing up against them. When you say, "minnows", exactly what do you mean? The "minnows" sold in bait shows are usually shiners, which are members of the Carp family along with goldfish, and so are the so-called "rosy reds" often sold in pet shops as feeders. All of those fish are very high in a dangerous enzyme called thiaminase, which inhibits Vitamin B absorption, vital for survival and development of the snake. Thiaminase is especially dangerous for young, growing snakes, and can and usually does result in serious neurological issues. I've found it best to try and get them onto f/t mouse pinkies if possible, and if not that, then cut pieces of thiaminase-free fish from the supermarket, such as tilapia, trout, ocean perch, salmon or flounder. The article I linked refers to feeding predatory fish, but the information can be applied to any piscivorus animals.
Thiaminase

thanks for the tapping advice. Yes I know all about thiaminase and long term effects, this is just about getting them started before switching them to mice. Neither rosy reds or goldfish or any frozen fish are really healthy diets for watersnakes, except occasionally.

and although I'm inclined to agree that certain fish species are best avoided, I'm sure you know that there are no actual data on harmful effects on growth or mortality rates in any piscivorous snake in relation to thiaminase.

I've seen hatchlings in the wild taking river shiners that beach themselves on the shore and presumed this is a large portion of their early diet. I don't think wild snakes avoid fish with thiaminase, their diet just has a lot of variety. You could mix things up with finger bass, tadpoles, mudminnows, darters etc from the nearest creek even in winter. I wouldn't expect a young snake to take prepared food, they haven't lived long enough to provoke the feeding response.