Akadama

Also sold as Double Red Line akadama · hard akadama · Acadama · Akadama (Japanese bonsai clay) · Japanese bonsai clay

Synonyms Ibaraki akadama · Akadama clay · Akadama soil

Akadama from generic is a specialty substrate with a 1–9 mm grain. It holds no nutrients of its own and pushes pH down, which is what decides whether it suits your plants and your shrimp.

At a glance

TypeSpecialty substrate
NutrientsNone (inert)
Grain1–9 mm
Brandgeneric (various Japanese producers)
Effect on pHLowers pH and KH
ShrimpSuits Caridina

Before it goes in

  • Akadama is a specialty substrate, 1–9 mm grain.
  • It is inert: it holds no nutrients of its own. Root feeders such as Cryptocoryne wendtii and Dwarf Hairgrass Mini need root tabs under them.
  • It pulls pH and KH down, which suits soft-water shrimp and most plants. It also works against hardscape that raises hardness — Seiryu Stone and Elephant Skin Stone — so the two partly cancel out.
  • It is rough on fish that sift the substrate. Something finer suits German Blue Ram and Julii Cory better.
  • It suits Caridina — the soft, acidic water they need is what it buffers towards.

What kind of substrate is it?

Specialty substrate with a 1–9 mm grain, holding no nutrients of its own.

Does it change pH?

Yes, it pulls pH and KH down and holds them there until it is exhausted.

Can I use it on its own?

Yes — Akadama is a complete substrate on its own.

What it goes with

More substrates

Sources (4) · checked Sep 2026