Aquarium gravel and sand
Gravel and sand are the substrate that sits on the base of the tank, and the main choice is not colour but grain size: gravel is easier to keep clean with a siphon, sand looks more natural and suits bottom-dwelling fish but needs a gentler cleaning routine. Either works for most freshwater community tanks; the wrong depth or the wrong grade for your fish is what causes problems.
Gravel versus sand
Gravel is the easier substrate for a first tank. Waste and uneaten food settle on top of it rather than in it, so a standard gravel siphon lifts debris out during a water change without disturbing the layer underneath. It also comes in a wide range of colours and finishes, including decorative pieces like our Roman Gravel in Sonic Blue, which is really about the look of the tank rather than anything functional.
Sand sits flatter and looks closer to a natural riverbed or lake bed, which suits corydoras catfish and other fish that dig or sift through the bottom looking for food — a coarse gravel can damage their barbels over time. The trade-off is that sand compacts, so it needs a different cleaning technique: hover the siphon just above the surface rather than pushing it in, or waste builds up under the surface instead of on top of it.
How much to buy
A depth of around 2-3cm is enough for a simple community tank with no live plants, and going much deeper than that with gravel serves no purpose other than using more of it. As a rough guide, allow roughly 1kg of substrate per 10 litres of tank volume for that depth, though bag coverage varies by grain size so check the pack.
Planted tanks are the exception — root-feeding plants need a deeper bed, often 5cm or more, and benefit from a nutrient-rich layer underneath a decorative gravel or sand cap. If you are planting the tank rather than just decorating it, buy for that depth from the start rather than topping up later and disturbing an established layer.
In this section
Everything below is in stock with us, priced with delivery worked out, and packed and posted by hand in the UK.
Tetra Goldfish Flakes
Complete goldfish flakes in several pack sizes, with a shared formula across the family
From£3.02
Tetra Goldfish Granules
Complete granules for goldfish, with a shared formula across both pack options
From£3.98
Tetra Prima Mini Granules
Slow-sinking granules for mid-water and bottom-feeding fish, blending herbivore and omnivore diets
£6.10
Tetra Aquasafe
A water conditioner that neutralises chlorine and heavy metals, with an added vitamin B mix
From£6.41
Tetra Pond Fish Food Variety Sticks
Complete Tetra Pond Variety Sticks in three colours, across four pack sizes
From£6.41
Tetra Koi Pond Fish Food Sticks
Complete fast-soaking Tetra Pond Koi Sticks, available in four pack sizes
From£6.41
Tetramin
Complete TetraMin flake food for ornamental fish, offered across several pack sizes
From£2.39
Tetra Temperate Flakes
Complete flakes for subtropical fish kept at 18–23°C, with vegetable ingredients
£6.99
Tetra Pond Fish Food Sticks
Complete fast-soaking Tetra Pond Sticks for pond fish, in seven pack sizes
From£4.77
Tetra Japan
Sinking dry pellets for fancy goldfish, with pack-specific label information shown clearly
From£4.56
Common questions
- Do I need to rinse aquarium gravel before adding it?
- Yes, rinse it thoroughly under running water until the water runs clear, because bagged gravel and sand carry dust from manufacturing that will cloud the tank for days if it goes in unwashed. A bucket and a hose outside is easier than doing it in a sink.
- Is sand or gravel better for a beginner fish tank?
- Gravel is the more forgiving choice for a first tank because it is quicker to clean with a standard siphon and more tolerant of an imperfect cleaning technique. Sand looks good and suits certain fish, but it rewards a gentler, more careful approach to water changes.
- Can I mix different colours or types of aquarium gravel?
- Yes, mixing colours or grain sizes is purely a look-and-feel choice and has no effect on water quality, as long as everything you add is aquarium-safe rather than gravel intended for outdoor or building use. Rinse each batch separately before combining them.
- Will gravel affect my aquarium's water chemistry?
- Standard inert gravel and sand sold for aquariums will not affect pH or hardness. Some decorative or calcium-based substrates can raise hardness over time, so if you keep soft-water fish, check the packaging says inert before buying rather than assuming every bag is neutral.
Related
Written by Matt Garnett, who runs Giddy Pets and is a lifelong pet owner — not a vet. This is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your animal. How we write these guides.