I agree with both posters, but wanted to add. . . it isn't *always* the case that you won't see them with leaf litter - for some reason I saw my Pangio babies MORE often when I had a nice carpet of leaves for them to squirm around in! Worth a try at any rate!
Too, you may want to bear in mind that not only do the tannins add color to the water (personally love the tea-colored tint!) but they can also soften it. How quickly depends on the Kh of the tap water you're using to begin with (water with a lower kh will allow the pH to drop more easily) and the type of leaf you end up using, lol as well as how many per gallon >.<. My understanding is that Indian Almond leaves contain more tannins, and so will have a greater affect on parameters with far fewer leaves than Oak, but please double check to be sure. (I have only used IAL in my tank)
I strongly recommend that you run a few bucket tests, with a handy
- as well as the Ph one that you *may* already have in the
(good deal on that right now ^_^), just to get an idea of how the leaves/tannins will effect your water, and how rapid the change will be. A rapid shift in pH isn't healthy for the critters, so best to be wary and test first!
ETA: There are so many different kinds of Oak trees in the world, do either of you know if all oak leaves are safe?! Ricky mentioned White Oak, specifically. . . for some reason I was under the impression that all were okay, but I'm not sure. I also know other types of leaf are okay, but these are the two I most often see used/recommended. . .