River Rock
Also sold as Smooth river stones · Pebbles · Cobbles · Round River Stone · Zen Pebbles
River Rock is an aquascaping rock sold by the piece, typically around 10 × 6 × 7 cm (3.9 × 2.4 × 2.8 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 | Smooth |
| Prep | Rinse |
| Default size | 10 × 6 × 7 cm (3.9 × 2.4 × 2.8 in) |
Before it goes in
- River 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.
- 4 different pieces of River Rock are modelled, so the one you place looks like one you could actually pick out of the bin.
- A default piece is 10 × 6 × 7 cm (3.9 × 2.4 × 2.8 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.
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
| River Rock | Lava Rock | Red Lava 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, Sharp edgesaquaticmotiv.com
- GHaquaticmotiv.com