[Pavel Chaloupka]

Sorry I was probably a little to brief with my answer. You may use just leaves just a loose layer of couple centimeters or if you want to put something under it, use granulated peat or fine sand. Gravel is not good in my opinion as Paros tend to dive in to the subrate when escaping and could hurt themselves. Pure leaves are great in my experience if you need to catch the fish to move them to some new tank, you just put the leaves out and catch the fish. Mainly with the small ones it is much easier than with some powdery substrate.