Choosing aquarium substrate: gravel vs sand vs planted soil
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Short answer: pick your substrate around the fish and plants you want. Gravel is the easy all-rounder, cheap and inert. Sand looks natural and suits bottom-dwellers like corydoras and cichlids that sift it, but compacts if left undisturbed. Planted (aquasoil) substrate feeds root-hungry plants and often lowers pH, at the cost of being pricier and finite. For a fish-focused community, inert gravel or sand is perfect. For a serious planted tank, a nutrient substrate or gravel plus root tabs will serve you better. Rinse anything inert before it goes in, and match the grain to your livestock.
Gravel: the easy default
Standard aquarium gravel is inert, meaning it does not change your water chemistry. It is inexpensive, hard-wearing, and easy to vacuum, which makes it the sensible default for most community tanks. Choose a smaller, smooth grain if you keep corydoras or other fish that root around, so they do not damage their barbels. Our bulk aquarium gravel and the wider gravel and substrate range cover most tanks. Rinse it well first — new gravel is dusty and will cloud the water otherwise.
Sand: natural and fish-friendly
Sand gives a natural look and is the best choice for fish that like to sift or burrow — corydoras, many cichlids, and eels all appreciate it. The trade-offs: it can compact into airless pockets if never disturbed, so stir the top layer during maintenance, and very fine sand can get pulled into filters. Keep the bed shallow and it is easy to live with. Sand is inert, so like gravel it needs root tabs to feed heavy plants.
Planted (soil) substrate: for plant tanks
Purpose-made planted substrates come in two broad types. Active aquasoils are baked-clay granules that hold nutrients at the roots and usually soften and acidify the water — excellent for demanding plants and shrimp, but they exhaust over time and are more expensive. Porous clay gravels such as Seachem Flourite are a middle ground: they feed roots and last the life of the tank, and you can use them alone or capped with gravel. If your plants are root-feeders in an inert substrate, add root tabs to make up the difference.
How deep, and capping
For most tanks, aim for roughly 1.5 to 2 inches of substrate — enough to root plants and give a natural look, without building deep, airless layers. A popular planted-tank approach is to cap a nutrient soil with a thin layer of gravel or sand, so you get the feeding benefit of soil with the tidy look and easier maintenance of gravel on top.
Match it to plants and fish
If plants are the priority, start with the plants and work back to the substrate — our guide to easy live plants pairs well with this. Browse live stock in the live plants and plants collections. And if you are setting up your very first tank, your first aquarium puts substrate in the context of the whole build.
Written by the team at Tropical Fish Imports in Lethbridge, Alberta. Last reviewed August 2026.
Not sure which substrate suits your plans? Tell us what fish and plants you want and we will point you to the right one — visit the shop, call 403-380-4506, or send us an email.