You may be concerned if you see small bubbles forming under the leaves of your live plants however you should really give yourself a pat on the back for doing a sterling job of keeping live tropical plants!
There are 2 reasons why this could be happening:
- Strong water current that contains a lot of air bubbles
- Photosynthesis is taking place. In this case the plant is taking carbon dioxide from the water and making oxygen in the form of the bubbles you see. Some aquarium keepers call this “pearling”
Neither case is anything to worry about and certainly if it is the second cause then you are doing a good job of keeping tropical plants and will have a thriving healthy luscious planted aquarium.