Thanks for the advise. I have a five gallon glow tank with a Cory cat and 4 fancy goldfish. I tested the water and said it was high ammonia. Also tested straight tap water and bottled . Same results. Bad test strips I’m assuming? We’ve had the tank for several years but only had the goldfish for a about 3 months. Cory cat is fine and the tank is clean so maybe my eater was just old? He grew abnormally large from what I was told he would be. He was almost 5” long! Maybe he ate too much. Still confused. We had glow fish before the golds that were almost 3 years old before they died. We are not in city water, but a well.