Shiny has fin rot.
His fins looked a little weird on the edges but I thought they were starting to curl like Fishie's did because of the hard water. But then today I came home (I hadn't been home since yesterday morning) and his dorsal fin is red on the edges and has a hole in it.
Of course I did a 100% water change and added Stress Coat and AQ Salt to the water, but I had also collected dried oak leaves from my parents yard today. Oak leaves help with fin rot, right? The same as IAL? So I tore off a piece of an oak leaf and put it in the water (rinsed it off first), but am I just supposed to let it float in the water or was I supposed to sort of crush it up and make a tea out of it? What's the best way to get the tannins in the water from the oak leaf?