UNS · Stone
Ancient Stone
Iwagumi keepers who like the Manten look and want a slightly darker, more angular stone.
4 models
UNS · Stone
UNS Hakkai Stone
Also called Pa-Hai or bug-eaten stone, Hakkai is smooth and rounded with eroded pits and a blue, grey and green cast. It is one of the heaviest stones in the hobby, so a given weight buys fewer, smaller pieces.
Updated
Best for
River-style scapes and calm Iwagumi with grassy plants like Dwarf Hairgrass or Blyxa.
Worth knowing
Very dense and pricey per kilo, so order more weight than your usual rule of thumb to get a spread of sizes.
What stands out
- 10, 20 and 30 lb lots plus a 5 lb bag of accent pieces
- Blue-grey with green undertones
- Smooth, rounded shape with natural pits and grooves
- Safe for fancy goldfish and bettas thanks to soft edges
Models and specs
| Model | Weight | Contents |
|---|---|---|
| 10 lbHAK0010 | 4.5 kg | – |
| 20 lbHAK0020 | 9.1 kg | – |
| 30 lbHAK0030 | 13.6 kg | – |
| Accent pieces (5 lb)HAKAS05 | 2.3 kg | Small accent stones |
- Brand
- UNS
- Effect on water
- Inert (per seller)
- Colour
- Blue, grey and subtle green
- Texture
- Smooth, rounded, pitted
- Prep
- Rinse and scrub well before use
Figures from Glass Aqua's product listing. Makers revise products, so check the current figures before buying. Photos supplied by the brand or its distributor.
Compare with
Browse all hardscape
UNS · Stone
Ashen Stone
Minimal or river-style scapes that want bright, soft stone against lush green planting.
3 models
UNS · Stone
Black Lava Rock
Budget-friendly builds, nano tanks and moss-covered scapes that need plenty of stone volume.
1 model
UNS · Stone
Black Lava Rock Cave
Shrimp and nano tanks that need hiding spots, or scapers wanting planted pockets at different heights.
4 models
Frequently asked questions
Quick answers about the UNS Hakkai Stone, drawn from its specs.
Does Hakkai Stone affect water chemistry?
Inert (per seller).
How do I prepare Hakkai Stone before use?
Rinse and scrub well before use
Who is the UNS Hakkai Stone best for?
River-style scapes and calm Iwagumi with grassy plants like Dwarf Hairgrass or Blyxa.
Is there anything to watch out for with the UNS Hakkai Stone?
Very dense and pricey per kilo, so order more weight than your usual rule of thumb to get a spread of sizes.
What are the alternatives to the UNS Hakkai Stone?
Other hardscape worth comparing: UNS Ancient Stone, UNS Ashen Stone, UNS Black Lava Rock. Add any of them to the compare table to see the specs side by side.