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Bird & Aquarium Supplies Sizes Explained

By the Nest & Yard editorial teamUpdated 2026-08-094 min read

Our pick: the All Pond Solutions 1400EF Aquarium External Fish Tank Water Filter for Tanks Up to 600 Litres, Full Kit — the best Bird & Aquarium Supplies we tested, from £74.99.

Choosing the right size aquarium or bird supplies can be tricky, and understanding how sizes are described is key to creating a happy home for your aquatic or feathered friends. This guide breaks down the terminology used when listing these products on Amazon UK, explaining what those measurements actually mean in practical terms – particularly considering the space you have available at home. We'll look at examples like external filters from All Pond Solutions and internal filters from Aqueon and Interpet to help you find a suitable product for your household.

See the full range in Bird & Aquarium Supplies.

Planning ahead? Try our free Aquarium Fish Stocking Calculator

Pros

  • Handles tanks up to 600 litres with 1400L/H flow
  • Full kit includes filter media, hose and spray bar
  • Suits coldwater, tropical or marine set-ups

Cons

  • Larger footprint needs cabinet space behind the tank
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Aqueon Quietflow E Internal Power Filter, 20 Gallon

#2 Pick

Aqueon Quietflow E Internal Power Filter, 20 Gallon
Rated 4.5 out of 5 stars (3,240)
  • Plastic

Currently unavailable

Pros

  • Multi-stage filtration keeps water clear
  • Quiet motor suited to living-room tanks
  • Rated for tanks up to 20 gallons

Cons

  • Replacement cartridges are an ongoing cost
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£24.95

Pros

  • Compact size suits small coldwater and tropical tanks
  • Coir Tech Bio cartridges are plastic-free and simple to swap
  • High flow filtration stays quiet enough for a living room

Cons

  • Rated only for tanks up to 35 litres
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Pros

  • 5-stage filtration keeps water clear for coldwater and tropical tanks
  • Coir Tech Bio cartridges are simple to swap monthly
  • Sucker-mounted cradle makes installation straightforward

Cons

  • Sized for tanks up to 68 litres only — larger tanks need the CF2
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FAQ

What do 'L', 'M', and 'S' mean when describing bird cages?

These represent Small, Medium, and Large. Generally, an ‘S’ cage is suitable for a single budgerigar or finch, while an ‘M’ cage will accommodate canaries or small parakeets, and an ‘L’ cage offers more space for larger parrots like cockatiels.

How are aquarium tank sizes measured?

Aquarium dimensions are always given as length x width x height in centimetres (cm). Make sure you include the base of the tank when measuring, as this is crucial for ensuring it fits your desired location.

I have a small apartment; what size aquarium would be best?

A 20-30 litre aquarium would likely be suitable for a single Betta fish in a smaller apartment. Larger tanks require more space and filtration, so consider the available floor area carefully.

My living room is quite large – what are my options for a bird cage?

For a larger living room, you could look at cages measuring 90cm x 60cm x 120cm or bigger, potentially allowing for multiple birds or a larger parrot species with adequate enrichment.

What does 'gallon' mean when referring to aquarium volume?

A gallon is an imperial unit of liquid measurement, approximately equivalent to 4.5 litres. Ensure you convert gallons to litres (or vice versa) before comparing tank sizes.

How do I measure the space needed for a bird cage?

You'll need to account for the cage’s footprint, plus the width of any perches or accessories you plan to add. Allow at least 30cm of clearance around the cage for easy access and cleaning.

What factors should I consider when choosing an aquarium size?

Consider the number of fish you intend to keep, their adult size, and your budget – larger tanks require more equipment and maintenance costs.

Are there any specific measurements for different bird species?

Generally, smaller birds like canaries need a minimum of 45cm x 30cm x 30cm, while larger parrots (cockatiels, budgerigars) require at least 60cm x 45cm x 90cm for comfortable living.

What's the difference between a long tank and a high tank for an aquarium?

A ‘long’ tank prioritises horizontal space, ideal for fish that swim extensively, while a ‘high’ tank offers more vertical swimming space, suitable for species like Betta fish or those who enjoy exploring upwards.

How accurate should my measurements be when buying bird and aquarium supplies?

Aim to measure your space accurately to at least 30cm in length, width, and height. Consider adding an extra 15cm for manoeuvreability and ensuring the equipment fits comfortably.

In depth

Understanding Size Guides for Bird & Aquarium Supplies

Navigating the world of bird and aquarium supplies can feel overwhelming at first glance. A vast array of products are available, each seemingly tailored to a particular need, but often the size information provided is cryptic or confusing. This section aims to demystify the sizing terminology commonly used when purchasing these items for your UK home, providing practical guidance on selecting the right dimensions based on your space and intended use.

The fundamental challenge lies in the varied systems of measurement employed by manufacturers and suppliers. You’ll frequently encounter metric measurements (centimeters and millimeters) alongside imperial units (inches and feet). While conversion charts are readily available online, relying solely on them can lead to inaccuracies, particularly when dealing with curved surfaces or complex shapes like aquariums. A key factor is the internal volume of an aquarium – this is what dictates how much water you can actually house within it; simply measuring the external dimensions won’t give you a true sense of capacity. Similarly, bird cage size isn't solely determined by its footprint; height and overall interior space are equally important for providing adequate room to move and exercise.

Aquarium sizing is often described using terms like ‘length’, ‘width’, and ‘height’. However, these measurements refer to the *external* dimensions of the tank – the glass or acrylic housing itself. To accurately determine the internal volume, you need to subtract the thickness of the glass/acrylic from each measurement. This difference can be surprisingly significant, especially with larger tanks, and is a common source of error for new aquarists. Furthermore, consider the base size; this dictates how much space the aquarium will occupy on your floor – factor in sufficient clearance around all sides for access and equipment placement. For smaller tanks (typically under 60 litres), the glass thickness difference is less noticeable, but it’s still a crucial detail to bear in mind. Larger aquariums, particularly those exceeding 200 litres, demand meticulous measurement to ensure they fit comfortably within your chosen space and don't overwhelm the supporting structure.

Bird cage sizing follows a similar logic, though with added considerations for bird species. Cages are commonly described by their ‘overall dimensions’ – length, width, and height. Again, it’s vital to distinguish between these external measurements and the *internal* volume. Manufacturers will often specify the internal floor area, which is the most relevant figure when considering where your bird will spend its time. For smaller birds like canaries or finches, a cage measuring 60cm x 45cm x 45cm might be sufficient. However, larger parrots such as macaws or cockatoos require significantly more space – an internal area of at least 90cm x 60cm x 90cm is often recommended, and even larger cages are preferable for providing adequate room to move and play. The height is particularly important; taller birds need greater vertical space for flying and perching.

A frequent oversight among first-time buyers is neglecting to factor in the *additional* space required beyond the cage or aquarium itself. You’ll need space for equipment – filters, heaters, lighting, substrate, decorations – and for maintenance access. A small birdcage might appear perfectly adequate within a room, but adding all the necessary accessories will quickly fill up valuable floor space. Similarly, a large aquarium requires ample room around it for the filter system, plumbing connections, and potentially even a cabinet for storage. Carefully measure your available area *before* purchasing any supplies to avoid overcrowding and ensure a comfortable environment for your pet. Consider also that larger aquariums will require stronger stands or support structures than smaller ones; this can add significantly to both the cost and the physical footprint of the setup.

Finally, pay close attention to the specifications relating to mounting and installation. Some aquariums are designed to be freestanding, while others require a stand for stability. Bird cages often come with wall-mounting options, which need to be securely attached to a stud in your wall – ignoring this can lead to instability and potential hazards. Always check the manufacturer’s instructions regarding weight limits and mounting hardware requirements before making a purchase. Don't underestimate the importance of stable support; a wobbly aquarium or birdcage is not only aesthetically displeasing but also potentially dangerous for your pet. Remember, accurate measurement and careful planning are key to creating a safe and enjoyable environment for your feathered or aquatic companion.

The Nest & Yard editorial team

Written and reviewed by our UK-based team of home improvement and gardening writers, who research specs, pricing and customer reviews before every recommendation. Reviewed and updated on 2026-08-09.

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