Howdy, folks, So, I'm a bit befuddled. My tank has done well for months, with my stock of primarily rainbowfish maturing nicely. I added a piece of driftwood recently after soaking it for over a week and dumping out the bucket of water it had been sitting in twice a day. It was time for a water change, so that's when I added the wood, as well as two otocinclus, a golden angelfish and a female threadfin to complement my male threadfin which had been living in my tank for four months. A few days after adding the new stock and the driftwood, my male threadfin was torn to shreds. He was still alive, but barely, and didn't make it through the night. It looks as though the other fish simply niped all his fins clean off, whereas there was never any bullying in the tank prior. As I said, he had been in there for months. Would resetting all of the rocks and adding the driftwood cause my rainbows to get highly territorial? I've always heard (and practiced) shifting rocks and plants around in the tank when adding new fish so that old territories would be broken and new fish could be safely added. Just trying to get some opinions as to what might have gone wrong? Aquarium info is accurate and in my profile. Thanks for your opinions.