On the advise of many members, I tried decaffeinated green tea to add some tannins to my tank (5g divided) as a treatment for tailbiting and split fin after a couple of days of saltwater. I dropped in a decaf green tea (only) bag after a water change. About the time I could see a small change in the water coloration, both my fish started losing color. A grey-faced black-headed Betta is a horrible sight. They both got mopey and slow, although their breathing looked alright. And, for the first time I saw with my own eyes what clamped finnage looks like. Two 80% water changes and a couple of hours later, they appear back to normal. Scared the dickens out of me; can't imagine how they felt.