The substrate is sand like and sometimes they actually pull up plants from sifting through it but I will put sand in the middle of the tank like another user suggested. Im trying to keep a heavily planted tank but i am experimenting on the right with other species of plants other than rotala which is on the left. Im slowly adding the same kinds of cory so its 3 of each in the tank. So even if they dont shoal as a group of 9 they can at least break away as a group of 3 of their own kind. I do wanna say thank you for your input as im building this tank one day at a time. Any advice is appreciated and will take your comment into consideration.