A WIO first: the rounded expression of the iconic Ryuoh. Ryuoh Boulder brings the mountain DNA — deep greys and pale mineral veins — in water-shaped form, so you can compose with softness and flow. The result is a stone that reads calm and timeless, perfect for Iwagumi minimalism and convincingly natural river and stream biotopes.

Where classic Ryuoh cuts sharp ridges, Ryuoh Boulders are water-shaped: rounded silhouettes, softened seams, and quiet veining that glows under light. Drop a single piece in pale sand and the scene exhales; group a kit and you get meanders, bars, and eddies that feel discovered rather than arranged. Side light draws silvery highlights along the arcs; top light settles everything into a serene, mist-grey hush.

Let "current" lead the composition. Seat one main boulder slightly off-axis to set direction, then nest smaller pieces downstream to create natural banks and resting pockets. Half-bury a few to suggest sorting; leave negative corridors where water would move. For seamless scale transitions, veil the bases with WIO Accents Grey Chips, and echo the language with classic Ryuoh Stones for subtle ridge contrasts that frame the rounded masses.

The contours are livestock-friendly; crevices invite moss and epiphytes — use WIO PlantGlue for quick establishment. As a calcareous limestone, Ryuoh Boulders may gently nudge pH and hardness over time; routine water changes or buffering keep parameters steady.

Key Points

• Rounded, water-shaped expression of the iconic Ryuoh — deep grey with pale mineral veins
• Ideal for river biotopes, stream scapes, and Iwagumi minimalism
• Smooth silhouettes create natural-looking banks, meanders, and eddies
• Pairs with classic Ryuoh Stones and WIO Accents Grey Chips
• Calcareous — may gently raise pH and hardness over time

Characteristics

• Type: Calcareous limestone (rounded/tumbled form)
• Color: Deep grey with pale white mineral veins
• Texture: Smooth, rounded, water-shaped surfaces with softened seams
• Stone size: Mix sizes from 5 to 30 cm
• Water Hardness: Calcareous — may gently raise pH and hardness over time; regular water changes maintain stability

Availability at Cuboid Nature Aquarium

• Nano Box — 5 kg (11 lb): WIO's curated size mix, hand-selected assortment of stones from 5 to 30 cm
• Box — 11 kg (24 lb): WIO's curated size mix, hand-selected assortment of stones from 5 to 30 cm
• In-Store: Visit us in Pipersville, PA to hand-pick individual stones by the pound — choose exactly the pieces and sizes you want for your layout

Usage

• Suitable for both aquatic and terrarium environments
• Rinse rocks and stones with water before use; use a brush to clean before introducing to the aquarium
• Avoid placing rocks directly on the glass — place substrate or WIO LandForms beneath the hardscape first
• Always secure stones, especially when stacking; use WIO ScapeBound to prevent movement during maintenance
• Position stones a few centimeters/inches away from aquarium glass walls to facilitate maintenance
• Control any alterations in pH and kH by regular water changes with osmotic or soft water, or by using a water softener if necessary
• Safe for fish, shrimps, and other aquatic animals

Available from Cuboid Nature Aquarium — Authorized Retailer for WIO.