7 Secrets About 5 Gallon Fish Tank In Litres That Nobody Will Share With You

August 18, 2026

Navigating the 5-Gallon Fish Tank in Litres: A Comprehensive Guide for Aquurists

When starting an aquarium hobby, one of the most typical questions novices deal with focuses on measurements. Specifically, aquarium sizes are frequently pointed out in gallons, especially in North American content. However, for those using the metric system, picturing these measurements can sometimes be puzzling.

If you are looking at a compact starter aquarium, you have likely came across the popular 5-gallon aquarium. However what does that translate to in the metric system?

Simply put, a basic 5 US gallon fish tank is roughly 18.92 litres.

This thorough guide will check out the precise metric conversions, what a tank of this size suggests for your water pets, how to set it up, and whether it is the right choice for your space.

1. The Numbers: Converting Gallons to Litres

Before diving into stocking levels and equipment, it is essential to understand the precise math. Depending on whether you are referencing United States gallons or Imperial gallons (utilized traditionally in the UK and Canada), the metric conversion differs a little.

Gallon Type

US/Imperial Value

Precise Conversion in Litres

Rounded for Everyday Use

US Gallons

5 United States Gal

18.9271 Litres

18.9 Litres

Imperial Gallons

5 Imp Gal

22.7305 Litres

22.7 Litres

Keep in mind: In the aquarium pastime, “gallons” practically constantly refers to United States gallons unless stated otherwise.

Comprehending that your 5-gallon tank holds approximately 19 litres of water is crucial. Water weighs approximately 1 kilogram per litre. This indicates a completely filled 18.9-litre tank— once you consider substrate, designs, and devices— will weigh around 20 to 22 kgs (44 to 48 lbs). You must guarantee your furniture can comfortably support this weight.

2. Is a 19-Litre Tank Right for You?

A 19-litre (5-gallon) tank falls into the category of a nano aquarium. These compact environments have actually become tremendously popular due to their small footprint, making them ideal for workplace desks, dormitory, or small apartments.

Nevertheless, before acquiring, it is crucial to understand the physics of small fish tanks.

The Myth of “Easy Maintenance”

Beginners frequently presume that smaller sized tanks are easier to maintain since there is less water to clean. In truth, the reverse is often real.

In a 19-litre body of water, chemical modifications occur much faster than in a 100-litre tank.
If a fish overindulges or a plant rots, the ammonia and nitrate levels can surge precariously in a matter of hours.
Water criteria (temperature level and pH) change more quickly.

For that reason, running an effective 19-litre aquarium requires diligence, steady regimens, and a dependable water testing package.

3. What Can Live in a 18.9-Litre Aquarium?

Because of the limited volume, stocking a 19-litre tank needs cautious preparation. You can not keep big fish, nor can you keep schooling fish that need long swimming areas.

Here is what can easily reside in a 5-gallon/ 19-litre tank:

A Single Betta Fish (Siamese Fighting Fish): A 19-litre tank is extensively considered the gold requirement minimum size for a single male or female Betta. It provides adequate space to explore, particularly if planted densely.
Freshwater Shrimp: Cherry shrimp, Amano shrimp, and crystal shrimp thrive in nano tanks. You can easily keep a colony of 10 to 15 shrimp in 19 litres, as their bioload (waste production) is exceptionally low.
Nerite or Mystery Snails: Snails make great cleanup crews. A single nerite snail will help keep algae under control.
Nano Fish Species: Very couple of fish species are ideal for a tank this size. Endler's livebearers (males just, to prevent overbreeding) or Microdevario kubotai (emerald dwarf rasbora) can work, however only if the aquarist is knowledgeable and maintains extensive water quality.

What NOT to Put in a 19-Litre Tank

To make sure animal well-being, prevent keeping the following species in a 5-gallon aquarium:

Goldfish: Goldfish produce huge amounts of waste and grow far too big. Aquarium Measurements Calculator need a minimum of 75+ litres for a single fancy goldfish.
Tetras, Danios, or Barbs: These are schooling fish. To be delighted, they need to be kept in groups of 6 or more and need horizontal swimming area (a minimum of a 38-litre/ 10-gallon tank).
Plecostomus (Plecos): Even the smaller species (like the Bristlenose Pleco) grow out of a 19-litre tank quickly.
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4. Vital Equipment for a 19-Litre Tank

Establishing an 18.9-litre aquarium requires specific gear reduced to nano percentages.

Filtering: You will need a small, adjustable hang-on-back (HOB) filter or a sponge filter rated for as much as 20 or 30 litres. Ensure the flow rate isn't too strong, as fish like Bettas battle versus heavy currents.
Heating system: Most tropical fish require a steady temperature in between 24 ° C and 26 ° C(75 ° F— 78 ° F ). A little 25-watt submersible heating system is generally enough for a 19-litre volume.
Lighting: Simple LED lights are perfect. If you desire to grow live plants (like Anubias, Java Fern, or Bucephalandra), guarantee the light has a spectrum matched for plant development.
Thermometer: Crucial for keeping track of water stability in a little volume.
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5. Step-by-Step: Setting Up Your 19-Litre Aquarium

If you are prepared to bring your 5-gallon tank to life, follow this basic setup summary:

Rinse and Position: Place your tank on a durable, level surface away from direct sunshine (to avoid algae flowers). Rinse the glass with warm water— never ever use soap or chemicals.
Include Substrate: Add 2 to 4 kgs of aquarium gravel or nutrient-rich aqua-soil, sloping it slightly toward the back for visual depth.
Install Hardscape & & Plants: Arrange driftwood, rocks, and live or silk plants. Live plants assist absorb nitrates and support the water chemistry.
Fill with Water: Gently put your 18.9 litres of water into the tank. Using a plate or a plastic bag at the bottom helps prevent troubling your substrate layout.
Include Water Conditioner: Treat the faucet water with a dechlorinator to eliminate hazardous chlorine and chloramines.
Set up Equipment: Set up your filter and heating unit, then plug them in.
The Nitrogen Cycle: Crucial Step. Permit the tank to cycle for 2 to 4 weeks before adding any fish. This constructs up helpful bacteria that convert harmful ammonia into safe nitrates.

Summary Table: 5-Gallon Tank at a Glance

Criterion

Metric Value (Litres/ cm/ kg)

Imperial Value (Gallons/ inches/ pounds)

Water Capacity

~ 18.9 Litres

5 United States Gallons

Total Weight (Full)

~ 20— 22 kg

~ 44— 48 pounds

Typical Dimensions (Standard)

~ 40 x 20 x 25 cm

~ 16 x 8 x 10 inches

Perfect Stocking Limit

1 Betta OR 10— 15 Shrimp

Minimum Heater Size

25 Watts

Understanding that a 5-gallon fish tank equates to 18.9 litres is the initial step toward developing a prospering aquatic environment. While compact and ideal for tight areas, a 19-litre tank demands regard, persistence, and regular upkeep. By equipping it properly— perhaps with a magnificent Betta fish or a colony of colorful freshwater shrimp— you can create a sensational, dynamic piece of nature right on your desktop.