Substrate Choices for Snails, Shrimp and Planted Tanks
The substrate isn't just the floor of the tank — it affects water chemistry, burrowing behaviour and safety for soft-bodied livestock. This guide compares sand, gravel and aquasoil for mixed invertebrate and planted setups.
Sand
Fine, rounded sand is generally chemically inert — it doesn't meaningfully affect pH, GH or KH — and it's the substrate most closely associated with burrowing species. Malaysian Trumpet Snails in particular rely on soft substrate they can move through freely; our MTS guide covers how that burrowing behaviour helps prevent anaerobic pockets forming.
Not all sand is equal, though. Sharp-edged or coarse silica sands sold for other purposes can be abrasive to the soft feet of shrimp and snails and are best avoided — look specifically for aquarium-safe sand described as fine and rounded. Sand can compact over time if nothing disturbs it, which is where a healthy population of burrowing snails becomes genuinely useful rather than incidental.
Gravel
Standard aquarium gravel is also chemically inert in most cases, and its larger particle size means it doesn't compact the way sand can, giving good flow of water and debris down to the substrate surface. The trade-off is that it isn't suited to burrowing species — the gaps are too coarse for MTS to move through comfortably, and food and waste can settle between the larger particles rather than being processed.
Gravel with sharp or angular edges carries the same risk to soft-bodied shrimp and snails as coarse sand does — rounded, smooth gravel is the safer choice for any tank housing invertebrates.
Aquasoil (Active Substrate)
Aquasoil is a different category entirely. Marketed heavily toward planted and shrimp tanks, it's an "active" substrate — meaning it chemically interacts with the water rather than sitting inert. Most aquasoils gradually lower pH and soften GH and KH through ion exchange, and many release a degree of ammonia when first submerged as part of the manufacturing process breaking down.
The softening effect that makes aquasoil popular for plants can work directly against shell-building snails. Lower GH means less calcium available for shell growth, and lower pH accelerates shell erosion in species like Ramshorns and MTS. If you're running a mixed planted and snail tank on aquasoil, monitor GH closely and be prepared to supplement calcium — see our GH & KH guide for more detail.
The initial ammonia release is also worth planning around — a freshly set up aquasoil tank typically needs a longer, more carefully monitored cycling period before any livestock, shelled or otherwise, goes in. See our Water Testing 101 guide for what to check for during this stage.
| Substrate | Water Chemistry Effect | Best For |
|---|---|---|
| Fine sand | Inert | Burrowing snails, shrimp foot safety |
| Rounded gravel | Inert | General community and non-burrowing setups |
| Aquasoil | Lowers pH, GH and KH; initial ammonia release | Planted tanks; monitor calcium if keeping shelled species alongside |
Quick Reference
- — Fine, rounded sand suits burrowing species like MTS and is generally chemically inert
- — Gravel is inert and low-compaction but unsuitable for burrowers
- — Aquasoil actively softens water — a benefit for many plants, a risk for shell-building species
- — Avoid sharp-edged sand or gravel around shrimp and snails
- — Fresh aquasoil setups need longer, closely monitored cycling before livestock goes in
Important Context
Effects vary between manufacturers and products — always check the specific substrate's own guidance alongside the general principles here, and test your water directly rather than assuming a fixed outcome.
Jack's Aquatics · Medway, Kent
UK Bred. Mineral Supported. Never Imported. — jacksaquatics.co.uk