zebra danio in trouble

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?

 

CAN YOU PLEASE HELP QUICKLY

 

Danios play a chase game, mine did all day very day. They are best kept in larger numbers so that one doesn't get picked on a lot, but the chasing is normal bahavior for them. Look and be sure none of them are getting nipped fins, that will be your sign that they are in trouble. From everything I have seen of my fish, they just chase, and chase, sometimes like playing tag.

Good luck with your wonderful new fish!

--R

 

How can I tell if one of them is getting nipped fins?

 

look for uneven edges to the fins, ragged looking or like a little half round/oval piece is missing. you might need a magnifying glass to check close.