But, from what I have been told, corn snakes can get along just fine on fish. And fish, while I own them and have affection for them, just don't give me the same sense of skin-crawling betrayal I get when seeing a pet snake eat a mammal. (I saw a friend's snake eat a mouse once, it really bothered me.) I mean, you feed FISH to fish a lot of the time. So, snakes that eat fish? PERFECT.
It's entirely possible that I have been told wrong, and corn snakes do need to eat live mice for nutritional needs or something, but I treasure the illusion while I have it that some day I could own one of those incredibly Pretty snakes. They deserve that Pretty, capital P. Preeeetty.