Ohko stone, sometimes called “Dragon Stone” is sought internationally by aquarium enthusiasts. The textured surfaces of the rock are aesthetically appealing with color varying from brown, to green, to even hints of red from time to time. (Valium) You’ll receive 6 stones ranging from 1.5 to 5 inches Every. This package works great for plant vase and nano plant tanks. Every order is different, as nature makes only one of Every stone. As Ohko stone is mainly dried clay, it really useful to wash and soak the stone for a few days before use. Since it’s clay based, Ohko stone can also be broken to create smaller pieces with a hammer and chisel.