>Nitrite of 0.5 ppm is not that significant. I'd be willing to bet it was the >chlorine levels in a large volume water change without treatment for >chlorine. If you want to deal with the nitrite and ammonia, add some plants. I figured it (nitrite) meant something because it's at the middle of the test range and the test booklet interprets it as "Change Water Now." You're right about the cause of death, though, I am almost positive it was the chlorine. What a moron am I! Oh, well. The tank was very poorly stocked, awaiting some new specimens. I can't really have plants in the tank since these fish eat plants. I'm not too worried, since my tankwater pre-change had no ammonia or nitrite in it. Stuart -- Stuart Hall (sturob@swbell.net) (gasdocstu@my-deja.com) ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@listbox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@listbox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!