http://forum.aqua-fish.net/ A forum devoted to aquarium fish, plants, techniques and fish keeping as a whole. en http://forum.aqua-fish.net/?topic=pearling-in-planted-tanks-#1 what is pearling in a planted tank. this is when plants are photosynthesising to produce oxygen after absorbing co2.when oxygen levels in the water have peaked and it cannot absorb anymore pearling occurs on the plant leaves.Bubbles will appear on the leaves that look like little pearls. Plants will only pearl if there are ample nutrients for good growth.Heavy planting of a tank will also produce this effect.Ample lighting is required , once the lights are off, pearling will stop. mickey 2008-05-29