With how much my Florida Banded Water snake poops in the water, I have to recommend a removable water container. What I currently use is actually a cat litter box that I put some aquarium plants into. I actually feed mine "fish jello", and an appropriately sized mouse. I just switch it up every feeding. Fish is a very lean diet, so it wouldn't be the only thing I feed them.
https://ball-pythons.net/forums/show...de-Garter-Diet
That's the recipe for the fish jello I used. I found out that you'll have to add in a bit more water though. It'll be cheaper than the silverside perches, and just as healthy as long as you feed mice every other feeding.