Fish safe oak species

[Veganville]

Anyone know if any oak species aren’t fish safe? I’ve seen some ambiguous references to not using live oak, but I can’t find any reasons why. There’s a significant amount of live oak and tan oak growing around my home, and I’d like to use it for scaping. I’ve added live oak wood and bark to a few test tanks, and it’s SUPER tanniny. So dark it looks like strong black coffee, and I can’t even see anything in the tank. 

Edited March 26, 2022 by Veganville

[JettsPapa]

I've also seen reports that live oak leaves aren't good to use, without details.  Before reading that I had put some in a ten gallon shrimp tank with no problems that I could tell.

Since seeing that ambiguous information I've stopped using them.  I have access to plenty of red oak, post oak, magnolia, and sycamore leaves, so I don't see any reason to push my luck.