I have seen this behaviour before several times, but in two situations only: (1) when the oxygen content of the water had become insufficient, or (2) when the pH has been lowered too quickly too much.
Paros are normally not used to that, since they live in slowly flowing waters with a good oxygen level. In tanks with still water sometimes the solved oygen may be reduced too much, and then they use their labyrinth. The same holds for changes of the pH. Quick changes are out in normal conditions. They can stand it, but they must use their labyrinths. They are equipped to do so, but not as a permanent method to get clear with wrong water conditions.
If this is the case one should act. The fish are not ill but the danger is given that they become ill if this situation continues over a longer period.
I have a supposition what the reason is in this tank that you describe (and which we can see now ourselves in the video):
It may have its cause in the introduction of the many new leaves. There are lots of leaves to be seen and they may have been introduced too quickly in too fresh a quality. In my view (1) the leaves are brought in too big a quantity compared to that rather small tank. in nature, there are such big layers of leaves, of course, but the water is running; its quantity is by far greater than in this small tank. But I presume (2) that the leaves were not handled before sufficiently by putting them in boiling water for some minutes. If this is done it is impossible for the pH to fall too quickly and it is equally impossible that the level of oxygen falls to quickly and too much for a fish that is not used to use its labyrinth. The Boraras breathing quicker than usual seem to indicate the same.
My proposal: Remove the leaves as soon as possible, boil them for some minutes, make a 60% water change and introduce the leaves again in half that quantity. I should predict that the strange behaviour ends almost presently.