betta behaviour

Question
I have just bought 2 siamese fighting fish. The are both in a reasonable size
tank with a divider down the middle.  In the first few days, the blue one had
always had his tail splayed out and flared his gill covers when the red one swam
near the divider.  The blue one would swim around violently and was quite
aggressive which i gathered was normal behaviour. However the red one was rather
disinterested and acted as if the blue one wasn't there, he did not retaliate
the behaviour.  He did not once open out his tail and never flared his gills,
but he was still quite active by himself and didn't look sick.  Just today, he
has started to become quite aggressive and is now showing the same behaviour
signs as the blue one.  I wanted to know if males go through agressive phases
where they are quite fiesty and then become disinterested.  Is it part of the
mating cycle?  

Answer
Hi Jessica-

I've noticed that when two males first start living as neighbors, there's usually one dominant male who does most of the flaring. Then, after a week, the second male "gets tired" of being picked on and decides to fight back. It's perfectly normal, after some time the quiet male should return to his semi-peaceful state.

Enjoy your little ones!
-Amber Worman