Rank #7 in Best Fish Tank 2026: 10 Ranked, £99.99 Buys 20 or 54 Litres
Fluval Betta Aquarium Kit, 20 L
Price and rating as shown on Amazon when we collected them. Both change.
The Fluval 20L Betta Aquarium Kit is the smallest tank in this guide, and it lands at number 7. It costs £99.99 — exactly the same as two other listings here, one of which holds 34 litres and another 54. Same money, well under half the water of the biggest of the three.
Two numbers on its own page do not sit comfortably together. The specification table lists an Item Weight of 136 g beside a tank sold as 20 litres; 20 litres of water alone weighs around 20 kg, before any glass, filter or lid. The rating is 4.3 out of 5 from 71 ratings, but the star breakdown printed next to it adds up to 100 (73 five-star, 15 three-star, 5 one-star, 4 four-star, 3 two-star). Everything on this page comes from the Amazon listing — we have not tested this tank ourselves.
How those 71 ratings break down
An average hides its own shape. This is the spread behind the 4.3 stars.
Specification
Exactly as published on the Amazon listing, field for field.
| Price | £99.99 |
|---|---|
| Rating | 4.3 out of 5, from 71 ratings |
| Capacity in the product name | 20 litres |
| Item weight (as listed) | 136 g |
| Star breakdown (as listed) | 73 five-star, 15 three-star, 5 one-star — 100 ratings in total |
| Brand and model | Fluval, model number A1338 |
| Manufacturer | Rolf C Hagen UK Ltd |
| Warranty | 1 Year |
What buyers actually say
Quoted from customer reviews on Amazon
Verified purchase“Excellent small 23l aquarium for my Betta. Incredibly easy to set up, perfect size! The light is fine to grow real beginner aquatic plants but anything other than that you may want to upgrade the light unit. The filter flow is spot on, not aggressive, and very quiet. The filter media looks very easy to replace! I like the idea of the tap for water changes. I'm a huge fluval fan anyway due to their tank designs, affordability and excellent durability. If I had more room I would buy multiple ones of these!”
Verified purchase“Very nice quality as expected made by fluval. Pump works silently , very slow flow ideal for my pretty Betta . Perfect size”
What it is up against
The rivals it was ranked against in Best Fish Tank 2026: 10 Ranked, £99.99 Buys 20 or 54 Litres.
Questions people ask
How much does the Fluval 20L Betta Aquarium Kit cost?
The listing price is £99.99, the same figure as two other tanks in this guide that hold more water.
How big is the tank?
The product name says 20 litres. One review on the listing calls it a small 23l aquarium, so the litre figure is not stated the same way everywhere on the page.
How much does it weigh?
The specification table lists an Item Weight of 136 g. That is the figure the listing gives; it is not a weight we measured.
What is included with the Fluval kit?
The bullets say all necessary media is included — mechanical, chemical and biological — and the Included Components field names the filter. One reviewer says you will need to buy an air pump for oxygen and that it is not there.
What do buyers say about the Fluval 20L Betta Aquarium Kit?
The listing shows 4.3 out of 5 from 71 ratings, and its star breakdown adds up to 100 ratings, of which 73 are five-star.
What does the lighting do?
The bullets describe a natural soft glow LED light that is energy efficient and simulates naturally shaded Betta environments.
Is there a warranty?
The specification lists a 1 Year product warranty, with the manufacturer given as Rolf C Hagen UK Ltd.
Comments
Reader comments are not checked against the manufacturer's claims above.
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