I see, I have 30 Gal Aquarium and I have 5 Black Neon, 5 Albino, and 2 Oto. The neons always move to the back of the aquarium eveyertime I turned on the light but when I turned it off they starts to wander around but sometimes they would stay at the back of the background. So, I am doing some test by buying 3 more guppies to see if they have the same behaviour and when I put it in at first they wander around the tank for a while,then few minutes later they are following what the neons are doing. So, I was thinking maybe they are stressed because they are looking at their own reflection? Please give me a clarity XD