Read a artcle bout black water and popularity of it to aquarist. Checked even some pics too.here are some of them in attachment.black water refers water which have tanic acid and color like tea leaf.some time newly added bogwood made this effect naturally.heared that indian almond leaves are used to make this effect alternately and these leaves are beneficial for fish coz it have some medical effect. It lookz cool too. Now my question is that do oscar like this kind of environment? Is this tanin can harm them?