Thanks for the quick reply, I appreciate it!
I don't have a
test kit, so I don't know my readings.

I already had plans of vacuuming the gravel tonight, so I'll be doing a water change. He isn't acting sick at all, he's doing all of his usual activities and looks perfect...except for the hole, of course. I was so shocked to see him caught in the filter, I would have thought he'd been strong enough as well. He is still a farily little guy though, about three inches.
It's kind of a coincidence because I noticed last night that there was a lot of algae around the filter, so I decided to clean it. My boyfriend joked that Herman was going to feel insulted, like I don't think he cleans well enough...and that he will be mad that I got rid of his yummy algae he was saving for later. Then he gets stuck in the filter!
