I came home from work and one of my glofish was dead. They were all fine this morning when I fed them. I checked my water and it's showing my nitrites to be at .25 as well as my ammonia. My nitrates are at 10 and my pH is at 7.6. I've had the tank established for over 2 months and all of my other fish seem to be doing fine. All of my past tests my levels have been good (no ammo or nitrites low nitrates and stable pH) I test everyday. I also did a pwc
last night. Any thoughts on why I'm showing nitrites and ammo and why the fish may have died?