I just started a new tank a few weeks ago, 6 Tiger barbs original and
albino, 3 rainbow sharks, 3 catfish and 1 Plecostomus.
I've got caves and fake plants.

All of my fish have been acting pretty normal till a few hours ago.
All of my Tiger Barbs, and rainbow sharks are swimming at the top.
Not floating, just swimming at the top, with there mouths to the
surface, breathing the air.

Is this normal?
Could it because i added a new rock?
Could it be because i gave them freese dried bloodworms for the first
time today?

If you know what this means please help.

Thanks Monica.