Tannins are what gives tea its tan/brown color. They have some antimicrobial properties and help acidify the water slightly. The tannins that OFL mentioned are Indian Almond Leaves (IAL), which may be ordered online (try Amy on eBay), or dried Oak Leaves, which many of us have growing in our neighborhoods. (Although since it's summer, you may need to search a little to find this.) If all else fails, some people on this forum said they've used decaffeinated green tea successfully.
Unfortunately, I wasn't able to watch the video as I'm not on my regular computer. Therefore, I don't have a lot of information about what's going on, so I can't tell you much else. But if he's having difficulty swimming, then Epsom salt, per OFL's directions, is the way to go.
At this point, I wouldn't worry about him not eating. Lots of fish won't eat for a few days when they arrive in their new homes. Keep offering him a pellet (if that's what you're feeding him). If he doesn't eat it, remove it and try again later.