Any aquatic lizards/snakes that wouldn't be interested in fish?

[rudukai13]

I know this is a pretty big longshot but I was wondering if there would be any aquatic lizards or snakes (Note: Not turtles) that would be able to co-habitate with fish? Please note, I'm looking for something that will spend the majority of it's time in the water, not an animal that just needs a slightly larger water dish...