The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
Honestly, it can be sharp for fish having long flowing fins but with cory cats that isn't really a problem. See, with bettas it's a different story because of their long flowing fins. Also, the cory's shouldn't come in contact with the wood too often because of them being bottom feeders.
I've yet to notice an issue for my fish but do clip off sharp branches and find these soften over time in water as well. All my fish don't startle easily though (unless the food container fell over).