What is wrong with my leather?

[Newlin]

I got this leather about two weeks ago and this is how it has looked since I put it in my tank. Everything else in my tank is thriving except this. I have tried to put it low, mid, and high in the tank with different waterflows and nothing has helped. What am I doing wrong here? Everything is normal in the tank and like I said, everything else is doing good. I also got a kenya tree that is doing very well too. And I got it at the same time as this one. Please help.