I only have the gravel building up the land. On top of that is an aquatic soil. It's not suposed to harm frogs or figh is accidentally eaten but I'm going to top it off with the leaves andway just to be safe.
:looks good, i like the plants. i would only worry later on, when the tads turn into frogs, about them accidentally swallowing gravel during feeding, but you said that youre getting leaf mulch so that's ok. i would change the water every few days too. but it looks good!