Ohko, also known as Dragon Stone, gets its name due to its unique appearance and color. Dragon stone is a rock that resembles dragon scales due to its greenish brown hue and many crevices. Dragon stone is very popular in the aquarium hobby due to being lightweight, sturdy for stacking, unique look and it does not affect the water chemistry.Dragon stone is great for aquascaping due to its fragile-clay like structure, you can take larger pieces and break them with a hammer into smaller pieces to achieve a more rugged scape as well as smaller accent pieces for your aquarium.