What are acceptable nitrate levels for a FO tank? I was having high nitrate problems (60-80) in my mean tank(porcupine puffer, clown trigger, harlequin tusk) due to meaty foods basically decaying in the sand. So, I removed the sand bed in favor of a bare bottom tank but my clown trigger is still pale in color and has not been eating well for a couple months. I"m slowly working the nitrates back down but at what level does this affect the health of the fish?