Why do my tiger barbs always stay behind the bubbles on the air stone?
They swim around a lot but, they are always behind the bubbles?
Sounds like nervous or shy behavior.
How many tiger barbs? What size aquarium?
To be sure there are no issues with the water, test ammonia, nitrite and nitrate levels.
I'd say they are hiding out for sure. Do you have tall plants that they might go to also? Are there other fish that could be chasing them?
Well, the only thing inn the tank are the five tiger barbs, I know I need to get a few more in there.... There are some tall plants and some short plants.