The Fluval 57-litre tank is a mid-size aquarium designed for beginners and intermediate fishkeepers who want a complete, well-built setup without sourcing individual components separately. It's sold as part of Fluval's M-Series and Flex line depending on the market, and includes a built-in filtration chamber, LED lighting, and a fitted lid. If you're wondering whether it's a good buy for your situation, the answer depends heavily on what kind of fish you want to keep and whether 57 litres (roughly 15 US gallons) is the right volume for your plans.
This guide covers exactly what you get with this tank, what fish it suits, how to set it up properly, what the built-in equipment actually performs like, and what upgrades you might want down the line.
What's Included With the Fluval 57 Litre Tank
Fluval packages this tank as a complete kit, which is one of its main selling points over buying a bare tank and sourcing a filter and light separately. Here's what comes in the box depending on the specific model variant:
Filtration: The tank uses a rear filtration compartment built into the tank structure. The filter chamber is divided into sections for mechanical filtration (sponge media), biological filtration (BioMax ceramic rings), and chemical filtration (activated carbon). This three-stage design is appropriate for a tank this size and performs comparably to a hang-on-back filter rated for 10 to 15 gallons.
Lighting: The LED strip included is full-spectrum and has multiple lighting modes depending on the variant. Some versions offer a day/night cycle or a moon-mode setting. The intensity is adequate for growing low-to-medium light plants like java fern, anubias, and moss.
Lid: A fitted cover is included, which is important for many popular community fish that can jump. The lid design allows for feeding without full removal.
Heater: Depending on the market and retailer, a heater may or may not be included. Check the specific listing carefully. Many UK sellers include a Fluval heater; many US listings do not.
What's not included in most versions: substrate, water conditioner, and beneficial bacteria starter. You'll need to purchase these separately before cycling the tank.
What Fish Can You Keep in a 57 Litre Tank?
A 57-litre tank gives you meaningful stocking options but requires thoughtful planning. This is enough water volume for a proper community setup or a single-species display, but it's not large enough for fish with high territorial needs or that produce significant waste.
Good Options for a 57-Litre Tank
Small tetras: Neon tetras, ember tetras, black neon tetras, and cardinal tetras all do well in groups of 6 to 10 in this volume. They're active swimmers, color up beautifully under good lighting, and their bioload is low enough that the built-in filter handles them comfortably.
Rasboras: Harlequin rasboras and chili rasboras are excellent. A group of 8 to 12 chili rasboras in a planted 57-litre tank looks spectacular and stays healthy with minimal effort.
Corydoras: A group of 4 to 6 pygmy corydoras or false juliis work well as a bottom crew. They stay small, are peaceful, and help pick up uneaten food.
Bettas: A single betta with a small school of peaceful tankmates (like ember tetras) works well. The 57-litre volume gives a betta enough space to establish territory without constant stress.
Livebearers: Guppies, platies, and endlers can be kept in this tank, though guppies breed prolifically and you'll need a plan for managing population.
Fish to Avoid
Goldfish: Goldfish produce far too much waste for a 57-litre tank. Even a single goldfish will overwhelm the filtration and require frequent water changes to keep nitrates in check.
Cichlids: Most cichlid species are too aggressive and territorial for this volume. Dwarf cichlids like a single pair of Apistogramma can work if the tank is well-planted, but this is for more experienced keepers.
Larger schooling fish: Zebra danios and tiger barbs can technically survive here, but they're active, faster swimmers that do better in tanks over 80 litres.
Setting Up the Fluval 57 Litre Properly
Cycling the Tank Before Adding Fish
This is the step most beginners skip, and it's the leading cause of early fish deaths. The nitrogen cycle converts toxic ammonia (from fish waste and uneaten food) into nitrite, then into less harmful nitrate. It relies on beneficial bacteria that need 3 to 6 weeks to establish in a new tank.
To cycle the Fluval 57: 1. Fill the tank, add dechlorinator (Seachem Prime works well), and run the filter for 24 hours. 2. Add an ammonia source: a small pinch of fish food that will decay, or pure ammonia drops (easier to control). 3. Test water every few days with a liquid test kit (not strips, which are less accurate). 4. Once you see ammonia rise, then fall, and nitrite rise, then fall, your cycle is complete. 5. Do a 50% water change and add fish slowly.
Fluval's FX line of biological supplements can help speed the cycle if you add them during setup.
Substrate Choice
The tank has a flat glass bottom. You can use any substrate. For a planted tank, a nutrient-rich substrate like ADA Aqua Soil or Fluval's own Plant and Shrimp Stratum gives you better plant growth long-term. For a simple community fish setup without live plants, inert gravel (1 to 3mm grain size) is easier to maintain and vacuum.
Hardscape and Plants
57 litres gives you room for a genuine aquascape. A few larger stones (dragon stone or seiryu stone) plus some driftwood creates a natural look. Low-maintenance plants like anubias petite attached to driftwood, java fern tied to rocks, and a background of cryptocoryne wendtii or Vallisneria fill out a planted setup nicely with the included lighting.
How Well Does the Built-In Equipment Perform?
The Filtration System
The rear-chamber filter is functional and quiet. For a fish-only or lightly planted community tank with moderate stocking, it handles the bioload well. The mechanical filtration (sponge) needs rinsing every 2 to 4 weeks in old tank water (not tap water, which would kill the beneficial bacteria). The biological media (ceramic rings) should be left largely undisturbed.
The flow rate is adequate but on the lower side for the volume. If you're stocking moderately with tetras or similar community fish, it works. If you want to keep slightly messy fish or a heavier stocking level, an additional small sponge filter (like an Aquael Pat Mini) running alongside would give you more biological filtration capacity without disrupting the aesthetics of the main filter.
The LED Lighting
The included LED provides enough light for low-to-medium light plants. You won't be growing carpeting plants or anything requiring high light without supplemental lighting. Plants like monte carlo or glossostigma won't thrive under the stock light. For a typical planted community tank with anubias and java fern, it's perfectly adequate.
The light runs warm to the touch after several hours, which is normal for LED fixtures of this type.
Heating (If Included)
If your version includes a Fluval heater, it's a quality unit. Fluval's heaters are reliable and accurate to within 1 to 2 degrees Celsius. If your version doesn't include a heater, add an Eheim Jager or Fluval E Series heater rated for 50 to 100 litres. Don't use underpowered heaters for this tank size.
What Upgrades Are Worth Considering?
The stock setup is solid, but a few additions make a noticeable difference.
Additional biological filtration: A small sponge filter connected to an air pump adds significant beneficial bacteria surface area. This is especially useful if you're stocking close to the tank's capacity. Check our guide to best aquarium equipment for sponge filter and air pump recommendations that work well alongside built-in filtration systems.
CO2 injection: If you want to grow a wider range of plants, a small CO2 system (like a Fluval Mini CO2 Kit designed for tanks up to 60 litres) combined with a quality substrate and moderate lighting opens up the plant options significantly. This is optional for most beginners but makes a real difference for plant growth.
A proper test kit: The API Freshwater Master Test Kit is the standard recommendation. It tests ammonia, nitrite, nitrate, and pH with liquid reagents. You need this during cycling and for routine monitoring, especially in the first few months.
For a broader look at how the Fluval 57 fits into the range of available aquariums and equipment, see our roundup of top aquarium equipment which covers tanks across multiple price points and sizes.
Common Questions About the Fluval 57 Litre
Is the 57 litre too small for a beginner?
No, it's actually a good beginner size. Very small tanks (under 20 litres) are harder to keep stable because water chemistry can shift rapidly. A 57-litre tank has enough water volume to buffer small changes, which gives you more time to respond if something goes wrong. The tradeoff is that it's large enough to require a cycling period and regular maintenance, but not so large that the equipment costs become prohibitive.
Can I use this tank for shrimp?
Yes, and it works well for neocaridina shrimp (cherry shrimp, blue dream, etc.). Make sure the filter intake is covered with a sponge prefilter, because shrimp can get sucked into the filtration system. Cover all small gaps in the lid as well; shrimp are escape artists.
How often do I need to do water changes?
For a moderately stocked 57-litre tank, 20 to 30% every week or every two weeks is typical. If you're lightly stocked with a few small tetras, you might comfortably extend to biweekly changes. Test nitrate levels to guide this. If nitrates are consistently above 20 ppm, increase water change frequency.
Does it come with a warranty?
Fluval products sold through authorized retailers come with a standard warranty. The LED unit and filter are typically covered for 2 years. Keep your proof of purchase and register the product if the option is available in your market.
Wrapping Up
The Fluval 57-litre tank is a well-designed, complete kit that takes the guesswork out of sourcing compatible equipment. The filtration is reliable for the tank size, the lighting supports a planted setup with low-to-medium light species, and the overall build quality is what you'd expect from Fluval.
Where it works best: a planted community tank with small tetras, rasboras, and corydoras, or a single betta display. Where it falls short: heavier stocking, large or messy fish, or high-light planted aquascapes. If your plans involve any of those, either add supplemental filtration and lighting or step up to a larger volume. For the intended use case of a thoughtfully stocked community or planted display, it's a strong choice that won't need replacing as your experience grows.