That's what I was mostly worried about. If I fill it flush with the other side (well, right below flush of course), they can swim to the edge and crawl right out onto the fiber. But I was afraid that was *too much* water (I keep seeing pages on here saying 1-2 inches max.) That's about...5-6 inches so I was concerned (I know pacman frogs aren't the best swimmers but I keep seeing that RBT love water so when we first made it, I was thinking the more water the better.) But I'm always second guessing myself, hah.