If you are unsure, tell me, how are they otherwise? Do they eat fine, do they swim around the rest of the tank fine, and how is their swimming (as in does it seem restless, or does it look strong like your other fish)
I have a pleco that plays in my bubbles most of the time, he like to fight against them and it has it rewards on him, because boy is he a strong swimmer now..
Also fish seem to love having bubbles run along their bellys a well, if you have well tamed fish that will feed from your hands, try stroking their bellies very gently depending on their size, they will love you for it, and will to you first when ever you put your hands in the tank again (Does it with my angels)
But as they said above, they can just be enjoying themselves, think of it as a fishy theme park ride, like a rollercoster