Lava Rock
Also sold as Black Star Lava Rock · Round Lava Rock · Black lava rock · Black volcanic rock
Synonyms Volcanic rock · Black lava · Lava stone · Feather rock · Volcanic stone
Lava Rock is an aquascaping rock sold by the piece, typically around 10 × 8 × 8 cm (3.9 × 3.1 × 3.1 in). In the water it leaves the water chemistry alone, does not tint the water, and sinks straight away.
At a glance
| Material | Rock |
|---|---|
| Raises hardness | No |
| Tannins | None |
| In the water | Sinks right away |
| Edges | Sharp |
| Prep | Rinse |
| Default size | 10 × 8 × 8 cm (3.9 × 3.1 × 3.1 in) |
Before it goes in
- Lava Rock is inert: it will not move KH, GH or pH, so it is safe in a shrimp tank and in soft water.
- Before it goes in, rinse it.
- It has sharp edges — worth keeping in mind next to long-finned fish and around fish that sit on the bottom.
- 4 different pieces of Lava Rock are modelled, so the one you place looks like one you could actually pick out of the bin.
- A default piece is 10 × 8 × 8 cm (3.9 × 3.1 × 3.1 in); you can stretch it to whatever you bought.
Does it raise pH and hardness?
No. It is inert, so KH, GH and pH stay where your tap water puts them.
Do I need to prepare it?
Yes: rinse it before it goes in.
Will it tint the water?
No.
Is it shrimp- and fish-safe?
Yes. It does have sharp edges, which is worth a thought around long-finned and bottom-sitting fish.
What it goes with
- Plants you can tie or glue straight onto it: Anubias nana 'Petite', Subwassertang, Anubias barteri and Bucephalandra 'Green Wavy'.
- Substrates that leave the water where it is, the same as this one does: Walstad, ADA Amazonia and Colored Gravel.
Often compared with
| Lava Rock | Red Lava Rock | River Rock | |
|---|---|---|---|
| Raises | None | None | None |
| Tannins | None | None | None |
| In water | Sinks | Sinks | Sinks |
| Prep | Rinse | Rinse | Rinse |
More hardscape
Sources (2) · checked Sep 2026
- KH, Sinkingbuceplant.com
- GHaquaticmotiv.com