Sand is the ideal substrate for bottom-dwelling fish — corydoras, kuhli loaches and other diggers need soft, fine grains to sift through and burrow into without damaging their delicate barbels. It also looks clean and natural. This UK guide covers the best aquarium sands in 2026 and how to add sand without a cloudy disaster.
Here are our picks and how to use them.
- Sand is the ideal substrate for corydoras, loaches and other bottom feeders.
- Fine, rounded grains protect their barbels — sharp gravel can injure them.
- Dark sand makes fish colours pop; silica play sand is a safe natural choice.
- Rinse sand until the water runs clear and add water gently to avoid cloudiness.
Why sand suits bottom feeders
Corydoras and loaches sift sand through their gills and dig into it, which is impossible on sharp gravel — coarse substrate wears down their barbels and can cause infections. Fine, rounded sand lets them behave naturally and stay healthy. See our full substrate guide for the gravel-versus-sand picture.
Our top picks
Best natural look — smooth silica play sand. A fine silica/aquarium sand is safe, natural-looking and excellent for corydoras.
Best for planted tanks — inert dark sand. A dark aquarium sand makes fish colours pop and pairs well with root tabs for plants.
Best all-rounder — branded aquarium sand. A bagged aquarium sand is pre-cleaned and consistent, saving rinsing time.
Adding sand without cloudy water
Rinse sand thoroughly in a bucket until the water runs clear — this is the step people skip and regret. Add it to an empty or low tank, then pour water gently onto a plate or bag to avoid disturbing the sand. A little initial cloudiness settles within hours; your filter clears the rest. Clean sand during water changes by hovering a gravel vacuum just above the surface.
Frequently asked questions
Is sand good for corydoras?
Yes — sand is the ideal substrate for corydoras and other bottom feeders. They sift fine, rounded grains through their gills naturally, whereas sharp gravel can wear down and infect their delicate barbels.
How do you add aquarium sand without cloudy water?
Rinse it thoroughly until the water runs clear, add it to an empty or low tank, then pour water gently onto a plate or bag to avoid disturbing it. Any initial cloudiness settles within hours.
What is the best aquarium sand in the UK?
Fine silica or aquarium sand is a safe, natural choice for corydoras, while dark aquarium sand makes fish colours pop and suits planted tanks with root tabs.
— Jaqline Smalling, FishForever
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