Aquarium sand: what the different types are for
Aquarium sand comes in a few distinct types — fine silica sand, coarser natural sand, and coloured or coated decorative sand — and the right one depends more on what fish or plants you are keeping and how the tank is filtered than on which one looks best in the shop. Getting the grain size and preparation right matters more than the colour.
Fine sand vs coarser grades
Very fine sand suits fish that naturally sift through soft substrate, since a coarser gravel can be uncomfortable or impossible for them to dig through the way they would in the wild. It also gives a smoother, more natural-looking base for a planted or aquascaped tank.
The trade-off is that very fine sand compacts more easily than gravel, which can trap pockets of trapped gas underneath if it is not disturbed occasionally. A coarser sand or fine gravel mix is more forgiving for a tank without dedicated bottom-dwelling fish, and easier to keep clean with a standard gravel vacuum.
Coloured and coated sand
Coloured aquarium sand is usually a natural sand with a coating applied to change its appearance, and reputable aquarium-specific products are made to be inert and safe once rinsed, unlike sand intended for other uses such as building or play sand, which should never go in a tank.
If you want a specific look rather than a natural sandy colour, choosing a product made and sold specifically for aquarium use is the safer route, since it is tested for fish safety in a way a general-purpose sand is not.
Preparing and adding sand to a tank
Rinse any new sand thoroughly before it goes in the tank, regardless of type, until the water runs mostly clear rather than cloudy. Skipping this step is the single most common reason a newly set-up tank stays murky for days.
Add sand to an empty or newly set-up tank rather than pouring it into an established one with fish already in, since disturbing an existing substrate releases trapped debris and can cloud the water and stress the fish already living there.
Choosing what suits your tank
For a general community tank without bottom-dwelling species, a fine gravel or coarser sand is usually the easier option to maintain. For fish that specifically sift or burrow, a genuinely fine, aquarium-rated sand is worth the slightly higher maintenance.
Whatever you choose, match the substrate depth to what your filter and any plants need, and avoid mixing substrate types unevenly across the tank, which can create patches that behave very differently when it comes to cleaning and gas exchange.
What we stock
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 sand before using it?
- Yes, always rinse new sand thoroughly before adding it to a tank, regardless of the type, until the water runs mostly clear. Skipping this is the most common reason a newly set-up tank stays cloudy for days afterwards.
- Can I use playground or building sand in my aquarium?
- No, stick to sand made and sold specifically for aquarium use. General-purpose sand is not tested for fish safety and can contain additives or a chemical composition that is not suitable for an aquarium environment.
- Is sand or gravel better for a fish tank?
- It depends on what you are keeping. Fine sand suits fish that naturally sift or burrow through soft substrate, while gravel is often easier to maintain and better suited to a general community tank without bottom-dwelling species.
- Can I add sand to a tank that already has fish in it?
- It is better to avoid it where possible, since disturbing an established tank to add substrate can cloud the water and stress the fish already living there. Adding substrate before a tank is stocked is the more straightforward approach.
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.