Substrate

“Substrate” is another word for bedding, the material used to cover the floor of your pet’s enclosure. Since sandfish are fossorial (meaning that they like to spend most of their time underground), using the right substrate is critical to
ensuring their health and happiness. Fortunately, their ideal substrate is pretty easy to determine, as the answer is in their name!

Good sandfish substrates

• Jurassic Sands Reptile Substrate: This dune sand is almost exactly the same as what sandfish experience in their natural environment. It’s superfine, soft, and very diggable. At about $16 per 10 lbs, Jurassic Sands is the most expensive substrate on this list, but it’s arguably the best.
• Zoo Med Reptisand: Reptisand is a readily-available, low-dust sand substrate with no added dyes or chemicals. It’s made from finely ground quartz, making it silica-free and fairly similar to the sand in a sandfish’s natural environment. It generally costs about $15 for a 10-lb bag. 
• GlassBlast, fine: Glass Blast is a type of sandblasting material made from post-consumer recycled bottle glass. Due to a closed crystalline structure, it’s safer than traditional blasting sand, and the “Fine” grade is very soft, so you don’t have to worry about cuts. Plus, it’s environmentally-friendly! You can buy GlassBlast for about $4 per 10lbs.
• Play sand, washed: Play sand (also known as all-purpose sand) is not as fine-particled as the other options here, but you can get it for less than $1 per 10 lbs at any home improvement store.

Sandfish need at least 4-6” (10-15cm)  of clean sand for digging, burrowing, and “swimming”. They typically stay about 1-2” (1-3cm) under the sand, and generally don’t go deeper unless digging under something like a rock, water dish, or a buried hide box. However it is speculated that they may burrow deeper into the sand to cool off or seek moisture, so that’s why we recommend a deep substrate layer.