I have 2 pairs of clowns. A pair in my 65g and a pair in my 10g. I came to find that they live up to their name. Both pairs have unusual behavior, but its normal for them. The nesting behavior is very normal and you will have nothing to worry about. Enjoy their activeness now also because once they have become older and acustomed to the tank they will pretty much find one spot in their tank which they will claim as their own and stay in that area all day. While my new pair in my 10g remain actively swimming around. My pair in my 65 who are about one year old stay in the same spot all the time, until its feeding time.