I am a beginner and I am cycling my 10 gallon tank. I have 3 zebra danios in my tank and its been about 4 days. Yesterday I noticed that one of them is continuosly chasing the other two. One of them is kind of a loner, stays alone. I don't know if this is normal or if one is attacking the other two. At night I turned the lights off, of the tank and this morning when the lights were off, they they all seemed ok and there was no chasing around. Can someone please tell me what I should do? Is this normal?