Thanks.
I'm not sure if I will try another fish. :( It's WAY too hard to control the environment well enough in the school, I think.
According to the test strip, which I don't have on me to recall the numbrs, the water was one "spot" above the high end of safe. So it could have possibly been the water. I've heard not to add too much ph reducer at once because it's basically acid and will burn the fish if you add more than a drop a day, which is what I'd been doing. It still stayed high though.
I left all my water sitting for at least 24 hours though before adding fish.
Still, it's a school, water is yicky.
This sounds gross, but he was in the filter and bleeding from the gills when I found him. Did that mean that he couldn't get air, which would mean he was trapped in the filter? I had the filter off, so there was no pushing out of the water and the hole at the top could have been big enough to swim into.
The link to the filter is on a former post.
I just feel awfully bad about his short little life.