tiger barb floating face down

Question
hello, i just started my tank a week ago, i used all spring water from my nearest grocery store, and i have three medium tiger barbs and two rosey barbs (one male and female).  the two roseys and one tiger are doing great but my other two tiger barbs not so much, they tend to stay near the top, seem to be breathing harder than the others and sometimes go vertical (their mouth pointed towards the gravel and their tails towards the hood.  my water is around 79 and it looks good.  i noticed that my other tiger has been chasing both of them a lot and when he does they seem to swim normally.  i was wondering if they are just under stress from the bio cycle that the tank is going through or if the one tiger is being too merciless.  thanks a lot!

Answer
Hi Nate;

Tiger Barbs can be pretty aggressive. Rosy barbs are on the tame side compared to those little devils. Barbs will float around head down as they try to hide from the others. It would help to have more of each kind of barb so they will distribute their hyperactivity and nippy nature amongst a larger school. Since the tank is new it might not be safe to add more though. You might have to take the more aggressive guy out instead. Also provide more hiding places such as live plants for them to get away from each other.

Check the levels of ammonia and nitrite so they don't get too high. They will cause even more stress in the weaker ones. Here is a link to my article on new tanks to help you through that part;

http://www.xanga.com/Expert_Fish_Help

At Your Service;
Chris Robbins