fishtanktv.com - It is important to note how plants grow differently when they are above the water line versus when they are below the water line. Like i pointed out in the video. When a plant has its leafs under the water they are typically much larger and rounder. The reason for that is so that they can absorb more light with a larger surface area. I believe that plants grow skinnier leaves above the water is due to the fact that they are trying to grow up high into the atmosphere as they can to use the more easily available carbon dioxide. Plants have to go through a major shift when they are developing roots which is typically why they don't grow fast out of the start when you get them from the store. they have to adapt from A. being grown above water to being grown submerged and B. they have to adapt roots. Obviously you want plants with healthy roots. infact if you find a plant that has only a few leafs but a ton of good looking roots you could buy it if the few leaves it has are ok. It will have the ability to "eat" better with those roote (this advice is only for those doing dirt, no dirt or good substrate your screwed regardless) Roots are key as you can see in my ROOT DOWN video.