About 1/2 my fish in my 55 gal. are doing what the lfs calls flicking off of things in the tank, kind of like they are itching but there is no evidence of white spot or white dots like Ick. I did a water test yesterday and my Nitrites were 0.25 and nitratres were 160 so I immediately did a 50% water change and will continue to do 30% changes daily until I can get back to normal parameters. Could the spike in the nitrates be causeing them to flick off of objects? Also could this spike be due to over feeding as I caught my grand daughter dumping fish flakes in the 55 and she admits to doing this for a few days. I have since explained that she could kill the fish by over feeding and she decided that grandpa can feed the fish from now on. I should also mention that my ammonia is at 0 and ph is 7.4. Any help in this would be greatly appreciated. Jimmy