Endler's dying mysteriously?

[jarrod0987]

Test for Nitrites. In the mean time use something like Prime or Amquel Plus. It will detoxify Chlorine, Chloramine, Heavy Metal, Ammonia, and Nitrite. Nitrate is not important. Start doing water changes too. Also check to make sure the PH isn't getting to acidic and if you can afford it test for copper. It can leach in through pipes and kill things slowly.