The other day one of my fish died overnight in my established 10 gallon. I tested my waters with the api master kit and my nitrites were off the charts purple. My ammonia is zero and my nitrates are about 5 ppm
. Not sure why my ammonia didn't spike. My kit is not expired and it reads zero nitrites on my tap water and my 29 gallon tank so I don't think its my kit. I did an immediate 50% water change dosed with prime, and added some fritz zyme 7. Tested a few hours later and same result. I started to spread out my feeding to every other day. I continued to do daily water changes of about 30% for 4 days and still the same result. I was doing 25% weekly water changes before this but not actively testing my water. The rest of my fish seem to be doing fine but I'm not sure if that's just because of the prime. Am I lowering my beneficial bacteria by doing all these water changes? Not really sure what to do at this point. Any advice would be much appreciated.
I have a 10 gallon column with topfin 10 filter.
I have 1 dwarf gourami some neon tetras and a few mystery snails.