Rosy Barb a whirling dervish

[lonetrout]

My long finned rosy barb has developed a strange behavior in the last 24 hours. He is swimming in manic spins mostly upside down. He levels off after a while but when I look in on him he gets excited and swims all crazily. I have quarrentined him but I am at a loss as how to approach treatment. Tank levels are as follows:
Ammonia - 0
Nitrites - 0
Nitrates <20
Ph 7.6
Any help will be greatly appreciated.
*L*T*

 

[TONO]

thats just the way they are i had six of them, they will swim like that with no reason. (most hated fish for me, but they are a nice looking fish)