Substrate for a shrimp tank: gravel, sand or active soil?

Published October 19, 2026 · Updated October 19, 2026 · 5 min read

A red shrimp walking on fine reddish-brown gravel next to grass-like plants — Photo: Michael Skiba, Wikimedia Commons, CC BY-SA 3.0 (cropped)

Quick answer

For cherry shrimp, inert gravel or sand is the simple choice. Inert means it does not change the water.
Active soil lowers pH and softens the water. It is made for Caridina shrimp, and most guides say cherry shrimp do not need it.
Keep the layer fairly thin. Guides suggest roughly 1 to 7.5 cm (0.5 to 3 inches).
A dark color helps red shrimp show their color and hides dirt.

The three main types

Substrate is the layer on the bottom of the tank. In a shrimp tank it holds plant roots and gives shrimp a surface to pick through for food. Some types also change the water.

Type	Changes the water?	Good for	Watch out for
Inert gravel	No	Cherry shrimp and beginners	Few downsides. Vacuum it lightly during water changes.
Inert sand	No	Cherry shrimp	Can pack down and form pockets without oxygen if the layer is deep.
Active soil	Yes, it lowers pH and KH	Caridina shrimp	Releases ammonia at first. Keeps working for about 12 to 18 months.

Inert gravel

Shrimp Science calls gravel perhaps the lowest-maintenance substrate there is. It does not pack down. The small gaps let water reach plant roots, and they give a home to detritus worms, tiny harmless worms that eat waste.

Inert sand

Sand looks natural, and Shrimp and Snail Breeder prefers it in a thin layer. The risk is that sand packs down. Deep, packed sand can form pockets without oxygen, where bacteria make hydrogen sulfide, a toxic gas. To prevent this, keep the layer thin and poke it with a stick during water changes. Malaysian trumpet snails, which burrow through sand, also help.

Active soil

Active soil is made of baked soil granules. It softens the water and pulls the pH down, and it keeps holding the pH there. This is called buffering. pH is the scale of how acidic the water is, and KH (carbonate hardness) is what keeps pH from swinging.

Active soil has two catches. First, it releases ammonia for the first weeks or months, so Shrimp Science suggests letting the tank cycle and mature for a couple of months before adding shrimp. Second, it wears out. Shrimp Science says it buffers well for about 12 to 18 months, then becomes less effective.

Which shrimp need what

Shrimp	Preferred water	Substrate
Cherry shrimp and other Neocaridina	pH around 7 or a little above, with some KH	Inert gravel or sand
Crystal red, bee and other soft-water Caridina	pH about 5.5 to 6.5, with KH near 0	Active soil

Cherry shrimp do not need active soil. Shrimp Science explains that the water they like keeps its own pH steady through its KH. Flip Aquatics goes further and advises against shrimp soil for cherry shrimp, because it often keeps the water too soft for them.

Soft-water Caridina are different. They need acidic water with almost no KH, and active soil helps keep it that way. See Neocaridina vs Caridina for the full comparison.

If you want to feed rooted plants in inert gravel, root tabs are a common option. These are fertilizer tablets pushed into the substrate. Check that any fertilizer is safe for shrimp.

How deep to make it

Guide	Suggested depth
Shrimp Science	1 to 3 inches (2.5 to 7.5 cm)
Shrimp and Snail Breeder	0.5 to 1 inch (1 to 2.5 cm)

Both guides warn that a deeper layer raises the risk of gas pockets. Shrimp Science adds that a very thin layer may not hold its shape against the flow from the filter. If you want more height at the back of the tank, it suggests burying a few pieces of lava rock instead of adding more substrate.

Light or dark?

Most shrimp keepers choose a dark substrate. Shrimp Science notes that deeply colored shrimp, such as red cherries, keep their color better on dark ground, and that dark substrate hides waste. A light substrate looks bright but shows dirt quickly, needs vacuuming more often, and may make shrimp turn paler over time.

Adding it to the tank

Rinse inert gravel or sand in a bucket until the water runs mostly clear.
Do not rinse active soil. Shrimp Science advises against it. Follow the instructions on the bag.
Spread it evenly, then place rocks, wood and plants.
Fill the tank slowly. Pour the water onto a plate or a plastic bag so it does not dig holes in the substrate.
Cycle the tank before any shrimp go in. See how to cycle a shrimp tank.

FAQ

Do cherry shrimp need active soil?

No. Cherry shrimp do well on inert gravel or sand. Active soil lowers pH and softens the water, which suits Caridina shrimp. Flip Aquatics advises against it for cherry shrimp, because it often keeps the water softer than they like.

How deep should the substrate be in a shrimp tank?

Guides suggest roughly 1 to 7.5 cm (0.5 to 3 inches). A deep layer, especially of sand, can form pockets without oxygen, so most shrimp tanks use a fairly thin layer.

What color substrate is best for red cherry shrimp?

Dark. Shrimp Science notes that deeply colored shrimp such as red cherries keep their color better on a dark substrate, and it hides waste. On a light substrate they may turn paler over time.

How long does active soil last?

Shrimp Science says active soil keeps buffering well for about 12 to 18 months. After that it slowly becomes less effective and needs replacing.