Fluval Flex 57L Aquarium, The Perfect Choice For Beginners!

Fluval Flex 57L aquarium is a popular choice among fishkeepers. If you are a newbie, this 15-gallon tank offers some exciting features for your jumpstart! The size is not too big, but still spacious enough to build as your first community tank.

Fluval Flex aquariums can be an excellent choice for planted tanks. You can grow live plants along with decors to match your preference in this aquarium. Fluval Flex comes up with some distinctive features that make the product attractive to users.

The curved front of the tank is stylish looking, and a handy lighting system is visually appealing. Brilliant illumination is the focused feature of this aquarium.

Not only the outlook but also useful aquarium features combined altogether make a complete package for the aquarists.

If you are looking for your first-ever tank to start fishkeeping, the Fluval Flex 57L will not disappoint you.

Hagen HG Fluval Flex Aquarium Wht 57L, 15gal
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Hagen HG Fluval Flex Aquarium Wht 57L, 15gal
  • The Fluval 15 gallon flex freshwater kit is one of very few freshwater aquarium Kits to incorporate brilliant...
  • Item Package Height: 30.0
  • Item Package Length: 35.0
  • Item Package Width: 40.0

I’ll focus on the Fluval Flex 57L aquarium features that will somewhat benefit the aquarium keepers. I try to keep my review fact-based because you’ll invest your money relying on my review. So I believe the study should be unbiased and honest.

Fluval Flex 57L fish tank comes up with 2450 lux LEDs capable of creating a shimmering effect and an innumerable number of color combinations. Simultaneously, the 7500K LED lamp is producing a complete spectrum that can promote live plant growth.

An essential consideration of a lighting unit is how comfortably you can control it. This product features a super easy FLEXPad remote control. You can choose from an enormous number of color blending and special effects as per your liking.

The infrared remote sensor is sensitive enough, and easy access through the transparent glass aquarium makes the control communication smooth.

When you are an aquarist, you’ll find the main challenge is to maintain the aquarium environment healthy, explicitly ensuring the water quality. Therefore, an effective filtration system is crucial. 

Fishkeepers, especially beginners, often struggle to identify a suitable filter for the tank. Fluval Flex aquarium will relieve you from this hassle. 

The Fluval Flex 57L aquarium includes a three-stage filtration system. Three water purification stages are mechanical, chemical, and biological filtration, with foam, carbon, and BioMax as filter media. 

A multidirectional dual output feature will give you the option to customize the water flow. The flow customization option is useful, especially if you keep Betta fish or live plants like Frogbit or Duckweed in your aquarium. These inhabitants are not comfortable with high water flow. 

I want to add one more vital point. Filtration units are essential but not visually pleasing. In the Fluval Flex 57L Aquarium, the entire filtration system is hidden in a rear compartment. A stylish honeycomb mask conceals the filtration unit without hampering its primary function.  

The curved front of the aquarium can create an illumination of a broader view of an underwater world. Fetching lighting with appropriate décors can take the beauty of this aquarium to a whole new level.

You will love to see your aquatic pets swimming, relaxing, and playing in a nicely decorated home.


  • Perfect lighting spectrum for plant growth
  • FLEXPad remote control is super easy to control
  • An enormous number of color blending options
  • A three-stage filtration system ensures water quality
  • The hidden filtration system allows a better view of the aquarium
  • The curved front is stylish and creates an illusion of a more extensive view
  • The top cover opening allows easy feeding
  • Two years limited warranty


  • Only for freshwater use
  • Glass aquariums are fragile and prone to cracking if not carefully handled
  • The flow nozzles are on the same side as the feeding hole, which can blast the food around 
Fluval Flex 57L is a perfect match for ..

Some people prefer having various kinds of fish and making a perfect combination. For making such a community tank, you have to ensure sufficient space with versatile features.

In Fluval Flex 57L, you will get all of these. A 15-gallon aquarium is not huge but spacious enough.

Its filtration system has a multidirectional dual output for customized flow that allows a favorable flow for different kinds of fish.

A proper selection of substrate, along with the available features, can make this one an ideal community tank.

Small tanks are trendy for Betta keeping. The customized flow option makes this tank ideal for Betta, as this species is comfortable with low water flow.

Betta fish struggle if the flow output is very high, which will not happen in Fluval Flex. Pick a suitable heater to maintain warmer surroundings, and it will build this tank a perfect home for Betta.

The built-in lighting system is the best feature of Fluval Flex. It has so many variations that make it a perfect aquarium for keeping live plants. You can adjust the illumination from very high to low, just as much as your plant require.

On the other hand, if you keep floating plants, a high-flow pump is not suitable. But in Fluval Flex, you can customize the flow output.

The Fluval Flex 57L is straightforward to start and maintain. If you plan to have your first aquarium and have a moderate budget, pick it without hesitation.

This quality product is definitely going to make your first fishkeeping experience a pleasurable one.

Fluval Flex Comes with so many useful features, but it does not come with a heater. The heater is an essential item for an aquarium, and you cannot do without it. So you have to pick a suitable heater for the aquarium.

As a simple rule of thumb, while selecting a heater, the bare minimum watt you need is 2.5 times the tank volume. That means for a 15-gallon tank; a 37.5-watt heater is a minimum requirement.

But remember, the ambient temperature plays a vital role here. If you live in a too cold place, where the required temperature rise of water is 10 degrees Fahrenheit, for say, you will need a 150-watt heater. 

So choose between 50 to 150 watts. Hygger Titanium Aquarium Heater could be a good match with Fluval Flex.  You can take a peek at our top 10 picks of the best aquarium heaters

Suitable fish for fluval flex 57l aquarium

You can make it a Betta tank, but Bettas are not community fish. If you wish to make a community tank, pick from Danio, Molly, Platy, Guppy, Tetra, or Swordtail.

Fluval Flex Comes with so many useful features, including complete lighting and filtration system. But the rest you have to buy additionally. You definitely have to buy a suitable aquarium heater, decors, and other accessories like a water conditioner.

No, this model of the aquarium offers features only for freshwater use. The glass tank is useable both in the freshwater and marine aquarium. But the other accessories, especially the filtration system, are not designed for saltwater use.

Lighting is the Fluval Flex 57L fish tank’s focused feature and has good lighting options to grow live plants. This product’s lighting unit allows you to adjust the light from bright to low settings. Any freshwater plant (high, medium, or low light) is suitable for growing in this tank.  

The filter remains hidden in a rear compartment, and a stylish honeycomb wrap conceals the entire filtration unit. Still, it is not an Undergravel filter. The circulating pump sucks water through two intake vents, one at the upper left and another at the lower left.

There is a thumb rule for rough estimation that is one inch per gallon. That means in a 15-gallon tank, you can keep fish with a total of 15 inches in length (for example, three fish of five inches long).

It is only a gross estimation; however, in a 15-gallon tank with an effective filtration system, a combination of 6 to 8 small and medium fish is quite perfect for keeping.

Fluval is a renowned name in the fishkeeping arena. Over 20 years, they are providing many useful good-quality fishkeeping items. In my honest opinion, Fluval Flex 57L is one of the best aquariums of 2020 to start with, especially if you want to have live plants. 

The Fluval Flex 57L aquarium’s compact design makes it easier to place in any room with limited space. The pump is quiet enough that you can put it in your bedroom also. This elegant-looking fish tank will decorate any room perfectly. 

2 thoughts on “Fluval Flex 57L Aquarium, The Perfect Choice For Beginners!”

  1. I like your suggestions o f fish for the fluval 57 litres tank. Which order should I add the fish and how long should I leave between adding new fish?


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