SUBSTRATE & HARDSCAPE

Dragon Stone

Deeply textured, near-inert stone with dramatic crevices that host moss and shrimp.

Setup stage Substrate

Unplug before servicingHands out of the water firstDrip loop on every cableTest before you dose30 ppm CO₂ ceilingCycle before stocking

Substrate

Specification
Type	Clay-based sedimentary
Hardness	Soft — splits along layers
pH effect	Minimal
Colour	Olive-brown to rust
Texture	Heavily pitted and layered
Preparation	Scrub, no boiling needed

Technical parameters
pH effect	Negligible
KH effect	Negligible
Shrimp suitability	Excellent
Moss attachment	Excellent, holds naturally
Stacking	Group of interlocking pieces
Weight	Light for its volume

Dragon stone — Ohko stone — is a clay-based sedimentary rock with a heavily pitted, layered surface. Those crevices are the reason it is popular: they catch moss, they give shrimp somewhere to graze and hide, and they create the shadow and texture that makes a hardscape read as more than a pile of rocks.

Chemically it is close to inert. Dragon stone does not move pH or hardness appreciably, which makes it the safe choice for a soft-water shrimp tank or a fish that needs stable parameters. Its weakness is structural: the layered structure means it splits along the bedding planes, so it is best used as a group of interlocking stones rather than one large cantilevered piece.

Colour ranges from olive-brown to a warm rust tone, which reads as warmer and less stark than Seiryu stone. It suits Nature and Iwagumi layouts, though in strict Iwagumi the more angular Seiryu is the traditional choice.

Safety and welfare

Dragon stone is soft and can shear when dropped. Carry it supported on both hands and place it, do not drop it.
Scrub new stone under running water and check for any metallic inclusions or soft crumbling sections before it goes in.
A tall stack of any stone must be stable without glue. If a piece can be knocked loose by a net, it is a hazard to livestock and to the glass.

Using it well

Use an odd number of stones with one dominant piece. Two stones of equal size fight each other visually.

Plant moss into the crevices rather than on top. The pits hold it and it grows out of the gaps, which looks deliberate.

Photograph your hardscape before adding substrate. It is much easier to judge composition against a bare tank.

Good with

Cherry shrimpMonte CarloMossAnubiasBucephalandra

Note. Parameters are conventional ranges across the category, not the claim of any one manufacturer. Nothing on this page is for sale and no outcome for any plant or animal is guaranteed. Simulator output elsewhere on this site is a simplified model, not a measurement — confirm everything with a test kit and the equipment's own instructions.

Dragon Stone

Using it well

Good with

Works alongside