What A Sad Day!

So I have some bad news for all of you...Sushi died!! I think I know what happened, but it still came as a surprise this morning. On Saturday morning when I fed them he seemed just fine. I noticed on Thursday that a couple of my other fish seemed to be not doing so well, like they were having a little bit of a hard time breathing, but I figured it was just me being paranoid. I've been watching those two very closely and it seems like they are starting to swim a little crooked, but that could also just be paranoia in light of Sushi dying. The other two seem just fine. I never noticed Sushi acting funny either. I don't remember seeing him last night when I fed them because I wasn't really feeling well so I didn't stop to watch them eat like I normally do. I didn't think anything of it because he likes to hide in one of my decorations and usually it takes him a minute to come and eat. But this morning when I was feeding I didn't see him again and this time I looked under his rock and there he was dead. For quite a while it seemed too. I took a test of my water and it seems some of my levels have skyrocketed. I'm sure that's what killed him but I didn't expect it to be so sudden. So here's to Sushi, the best fish ever. I wonder if I put too many fish in there at once, but hopefully I can get this tank worked out so I don't keep killing things.