Aquarium gravel
Aquarium gravel is the substrate that lines the bottom of a fish tank, and the choice comes down to grain size, colour and how it interacts with your filter more than looks alone. The right gravel depends partly on what fish you keep and partly on how easy you want the tank to be to clean.
Grain size matters more than it looks
Fine gravel and coarse gravel behave differently once they are in the tank. Finer grains pack more tightly, which can trap waste and uneaten food near the surface rather than letting it settle, while coarser gravel lets debris fall between the pieces where a gravel vacuum can reach it during cleaning.
If you keep bottom-dwelling fish that dig or sift through the substrate, sharper or very coarse gravel can be uncomfortable for them, so a smoother, rounder grain is worth choosing specifically for that kind of tank rather than picking whatever looks best on the shelf.
Colour is a personal choice, with one practical side effect
Beyond appearance, gravel colour has a small effect on how visible waste and algae are day to day — a very dark or very light gravel tends to show buildup more clearly than a mid-toned, mixed colour, which can make it easier to judge when the tank needs attention.
Brightly coloured gravel is popular in smaller and beginner tanks and is not harmful to fish on its own, but it is worth checking that any gravel you buy is specifically sold for aquarium use, since it is treated and sized differently to gravel meant for other purposes.
How much gravel, and getting it ready
A shallower layer works for a simply decorated tank with just ornaments and fish, while a deeper bed suits a planted tank where roots need somewhere to establish. As a rough guide, most tanks look and function well with a layer a few centimetres deep across the base.
Rinse new gravel thoroughly before it goes into the tank, since bagged gravel usually carries dust from manufacturing that will otherwise cloud the water as soon as it is added. Rinsing until the water runs clear is worth doing properly rather than rushing, since it saves a cloudy tank and an extra water change afterwards.
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
- Does the colour of aquarium gravel affect fish health?
- No, gravel colour on its own does not affect fish health, as long as it is sold specifically for aquarium use. The main practical difference is how easily you can see waste and algae building up against a lighter or darker gravel, which is a cleaning consideration rather than a health one.
- How much gravel do I need for my tank?
- As a rough guide, a layer a few centimetres deep across the base works for most tanks, with a deeper bed if you are planning to add live plants that need somewhere for their roots to establish. It comes down to the size of your tank and what you intend to keep in it.
- Do I need to wash aquarium gravel before using it?
- Yes, bagged gravel usually carries dust from manufacturing that will cloud the water if it goes straight into the tank. Rinse it thoroughly in a bucket or colander until the water runs clear before adding it, which saves an unnecessary water change afterwards.
- Is gravel or sand better for a fish tank?
- It depends on what you are keeping. Gravel suits most community fish and is easier for beginners to clean with a gravel vacuum, while sand suits fish that naturally sift through a fine substrate. Neither is universally better — the right choice follows the fish rather than the other way round.
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.