Choosing the right size aquarium is the single most important decision you will make before buying — it affects the fish you can keep, the stability of the water, and the surface your tank sits on. Here is a plain guide to how tank sizes work.
Litres, dimensions, and what they really mean
Aquarium capacity is measured in litres of water. A 10–30L nano tank suits a desktop and a betta or a shrimp colony; 40–70L rectangles are the classic starter range for small community fish; 100L and above gives you room for larger shoals and proper aquascaping. Always check the physical dimensions too — two tanks of the same capacity can have very different footprints.
The weight rule everyone forgets
Water weighs 1 kg per litre. A filled 60L tank weighs over 75 kg once you add glass, substrate and decor — more than most flat-pack furniture is rated for. Before you buy, make sure your stand or surface is solid, level, and rated for the filled weight of the tank you have in mind. For anything above 100L, a purpose-built aquarium stand is strongly recommended.
A simple rule of thumb
Buy the largest tank your space and stand can genuinely support. Larger volumes of water are more stable and more forgiving for beginners, not less. If in doubt between two sizes, the bigger one is usually the easier one to keep healthy.
Browse our full range of glass tanks from 10L to 100L in the shop, or see our made-to-order large tanks from 120L to 500L.
