Japanese Ohko Rock - Dragonstone

Japanese Ohko Rock — Dragonstone | Iconic Aquascaping Hardscape With Dramatic Natural Texture

Japanese Ohko Rock, widely known in the aquascaping hobby as Dragonstone, is one of the most beloved and distinctive aquascaping stones available. Named for its extraordinarily textured surface — a complex labyrinth of deep holes, cavities, ridges, and channels that resembles the scales and skin of a dragon — it brings an unmatched level of surface detail and visual complexity to any aquascape. Its warm earthy tones of ochre, rust, brown, and grey shift subtly depending on lighting and moisture, giving it a rich, organic quality that looks equally stunning dry or submerged.

A favourite of both beginner and advanced aquascapers, Dragonstone’s dramatic texture and naturally varied form make it one of the most versatile and rewarding hardscape materials in the hobby.

Aquascaping With Dragonstone

Dragonstone’s deeply pitted, cavernous surface texture is its defining feature — and one that creates extraordinary opportunities in aquascape design. Its complex surface catches light and shadow in a way that flat or smooth stones never can, adding genuine depth and dimension to any layout. It works beautifully as a central focal point in nature-style and Iwagumi-inspired compositions, as a dramatic background anchor in larger planted tanks, or as a detailed accent piece in smaller nano aquascapes where its surface complexity can be appreciated up close.

Its porous, textured surface also develops an exceptionally rich coating of biofilm over time — making it a favourite in shrimp tanks where grazing surfaces are as valuable as visual impact. Mosses, Anubias, Java Fern, and Bucephalandra all attach and establish readily in the stone’s natural cavities and crevices, gradually colonising the surface and softening its form into something that looks genuinely ancient and established.

A Note on Water Chemistry

Dragonstone is generally considered inert and has minimal impact on water parameters — making it a safe choice for soft water setups, shrimp tanks, and planted aquariums where parameter stability is important. As with any new rock, we recommend testing its impact before adding it to a sensitive setup by placing a piece in a container of your tank water and checking pH and hardness after 24–48 hours.

Preparation and Safety

• Rinse thoroughly under clean tap water before adding to the aquarium — never use soap, detergent, or any cleaning products, as even trace residue is toxic to fish, shrimp, and invertebrates
• Do not boil or bake natural rock — extreme temperature changes can cause rocks to crack or shatter. A thorough rinse under running water is all that is needed
• Position stones carefully and ensure they are fully stable and secure before adding water — shifting rocks in a filled tank can crack glass or injure fish
• The deep cavities and holes in Dragonstone can trap debris over time — a gentle blast with a turkey baster or aquarium syringe during water changes keeps them clean
• Mosses, Anubias, and Bucephalandra attach readily into the natural cavities and crevices with fishing line or aquarium-safe glue
• Each piece is completely unique in shape, size, and surface detail — natural variation is part of the appeal

A Note on Sizing and Weight

Our rocks are sold by approximate weight in the following tiers:

• 0–5 lb — Small pack
• 6–10 lb — Medium pack
• 11–15 lb — Large pack
• 16–20 lb — Extra Large pack

Because these are natural stones, no two pieces are identical in shape, size, or weight — and it is impossible to pack rocks to an exact pound. Your order will always meet or exceed the weight of the tier you select, but may occasionally run slightly over. The number of individual pieces per pack will vary depending on the size and shape of the stones available at the time of packing. If you have specific sizing requirements or are planning a particular aquascape layout and need pieces of a certain scale, feel free to reach out before ordering and we will do our best to accommodate.

Ideal For

• Nature-style, Iwagumi, and contemporary aquascapes
• Planted aquariums as a primary focal point or accent hardscape
• Shrimp tanks — deeply textured surface develops exceptional biofilm for grazing
• Nano aquascapes where surface complexity adds visual impact at close range
• Mixed hardscape layouts alongside driftwood