Right now one of my goldfish is acting very strange, he was fine earlier today, he ate and acted fine. It wasn't until earlier I noticed that he was at the bottom of the tank not doing anything. I touched him to see if he was dead but he started to swim a little and then just stop and float bumping into things, just kinda dragging around. I checked the ammonia and it read 0.25 ppm which I believe is intoxic ammonia, correct me if i'm wrong. Anyway there doesn't seem to be any thing physically wrong with him, but he has never acted like this before. He has sat at the bottom of the tank at night, I just assumed that he was sleeping, but he has never been like this. The other goldfish are fine. Let me know if you might know what's wrong or if I am just peranoid. Thanks!