15 Things You Didn't Know About 5 Gallon Fish Tank In Litres

August 12, 2026

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

When starting an aquarium pastime, among the most common questions newbies deal with revolves around measurements. Specifically, aquarium sizes are often mentioned in gallons, particularly in North American material. Nevertheless, for those using the metric system, visualizing these measurements can sometimes be puzzling.

If you are taking a look at a compact starter aquarium, you have most likely encountered the popular 5-gallon aquarium. However what does that translate to in the metric system?

In other words, a basic 5 US gallon aquarium is around 18.92 litres.

This extensive guide will explore the specific metric conversions, what a tank of this size suggests for your aquatic animals, how to set it up, and whether it is the best option 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 US gallons or Imperial gallons (utilized historically in the UK and Canada), the metric conversion differs slightly.

Gallon Type

US/Imperial Value

Specific Conversion in Litres

Rounded for Everyday Use

United States Gallons

5 US Gal

18.9271 Litres

18.9 Litres

Imperial Gallons

5 Imp Gal

22.7305 Litres

22.7 Litres

Note: In the aquarium hobby, “gallons” generally describes US gallons unless stated otherwise.

Understanding that your 5-gallon tank holds approximately 19 litres of water is important. Water weighs around 1 kg per litre. This indicates a completely filled 18.9-litre tank— once you aspect in substrate, decorations, and devices— will weigh around 20 to 22 kgs (44 to 48 lbs). You must ensure your furnishings can comfortably support this weight.

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

A 19-litre (5-gallon) tank falls into the classification of a nano aquarium. These compact communities have actually become profoundly popular due to their little footprint, making them ideal for office desks, dormitory, or small apartment or condos.

Nevertheless, before acquiring, it is vital to comprehend the physics of little aquariums.

The Myth of “Easy Maintenance”

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

In a 19-litre body of water, chemical changes occur much faster than in a 100-litre tank.
If a fish eats way too much or a plant decomposes, the ammonia and nitrate levels can surge dangerously in a matter of hours.
Water criteria (temperature and pH) fluctuate more rapidly.

Therefore, running an effective 19-litre aquarium needs diligence, steady regimens, and a trustworthy water testing package.

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

Because of the restricted volume, stocking a 19-litre tank needs careful planning. You can not keep large fish, nor can you keep schooling fish that need long swimming spaces.

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. Fish Tank Calculator Volume provides adequate room to explore, particularly if planted largely.
Freshwater Shrimp: Cherry shrimp, Amano shrimp, and crystal shrimp prosper in nano tanks. You can comfortably keep a colony of 10 to 15 shrimp in 19 litres, as their bioload (waste production) is remarkably low.
Nerite or Mystery Snails: Snails make fantastic cleanup crews. A single nerite snail will help keep algae under control.
Nano Fish Species: Very few fish types appropriate for a tank this size. Endler's livebearers (males only, to avoid overbreeding) or Microdevario kubotai (emerald dwarf rasbora) can work, however just if the aquarist is experienced and maintains rigorous water quality.

What NOT to Put in a 19-Litre Tank

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

Goldfish: Goldfish produce huge amounts of waste and grow far too big. They require a minimum of 75+ litres for a single expensive goldfish.
Tetras, Danios, or Barbs: These are schooling fish. To be delighted, they require to be kept in groups of six or more and need horizontal swimming area (at least 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

Setting up an 18.9-litre aquarium needs specific gear reduced to nano proportions.

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

If you are all set to bring your 5-gallon tank to life, follow this fundamental setup summary:

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

Summary Table: 5-Gallon Tank at a Glance

Parameter

Metric Value (Litres/ cm/ kg)

Imperial Value (Gallons/ inches/ lbs)

Water Capacity

~ 18.9 Litres

5 United States Gallons

Total Weight (Full)

~ 20— 22 kg

~ 44— 48 lbs

Typical Dimensions (Standard)

~ 40 x 20 x 25 cm

~ 16 x 8 x 10 inches

Suitable Stocking Limit

1 Betta OR 10— 15 Shrimp

Minimum Heater Size

25 Watts

Comprehending that a 5-gallon aquarium translates to 18.9 litres is the initial step towards developing a flourishing marine environment. While compact and perfect for tight areas, a 19-litre tank demands respect, patience, and routine upkeep. By equipping it properly— perhaps with a magnificent Betta fish or a colony of vibrant freshwater shrimp— you can develop a spectacular, vibrant slice of nature right on your desktop.