Is grapevine safe for aquariums?

I've used it. It does take a LONG time to cure where it's not leaving tannins in the water and turning it yellow-brown. My fish loved it, the plecos loved chewing on it too. It will get some fungus looking stuff on it while curing out, my guess is the sugar sap is leeching out but it looks like fungus under the water - bonus was the fry and plecos ate it up as quick as it leeched out and grew a lot too. My gibby pleco put on 3-4 inches in 2 months chewing on the branches.