My snakes eat fish (fresh caught minnows from our stream), frozen fish, salmon, night crawlers and pinkies. I don't notice any smell in their tanks. They have to be the least stinkiest pet I have ever kept. The only time there is an odor is when the substrate gets wet and when it is very hot, like now But the smell is the substrate, not their poop! Also, must remove any uneaten food in this weather. That is one nasty smell if left overnight!