I got a leopard gecko about 3 weeks ago and I thought it needed a friend, so today I got another and put it in the terrarium. They are both pretty young. The new one went into the hide my old one was in, and he started fighting my new one! What do I do? They are too young to figure out if they are male or female. The guy at PetSmart said it was fine to put them together but I don't know what to do.