15 Things You Don'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 beginning an aquarium pastime, one of the most common concerns newbies deal with revolves around measurements. Particularly, aquarium sizes are regularly mentioned in gallons, particularly in North American material. Nevertheless, for those utilizing the metric system, envisioning these measurements can in some cases be puzzling.

If you are looking at a compact starter aquarium, you have most likely experienced the popular 5-gallon fish tank. But what does that translate to in the metric system?

Simply put, a basic 5 United States gallon aquarium is around 18.92 litres.

This detailed guide will check out the specific metric conversions, what a tank of this size implies for your water family pets, how to set it up, and whether it is the best option for your area.

1. The Numbers: Converting Gallons to Litres

Before diving into equipping levels and devices, it is essential to comprehend the precise mathematics. Depending Liter Calculator Aquarium whether you are referencing US gallons or Imperial gallons (used historically in the UK and Canada), the metric conversion differs a little.

Gallon Type

US/Imperial Value

Specific Conversion in Litres

Rounded for Everyday Use

US 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” usually describes United States gallons unless mentioned otherwise.

Understanding that your 5-gallon tank holds roughly 19 litres of water is vital. Water weighs approximately 1 kg per litre. This indicates a totally filled 18.9-litre tank— as soon as you aspect in substrate, decorations, and equipment— will weigh around 20 to 22 kilograms (44 to 48 lbs). You should ensure your furniture can easily 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 ecosystems have become profoundly popular due to their small footprint, making them ideal for workplace desks, dorm rooms, or little apartments.

However, before acquiring, it is essential to comprehend the physics of small fish tanks.

The Myth of “Easy Maintenance”

Beginners typically presume that smaller sized tanks are much easier to keep due to the fact that there is less water to clean. In truth, the reverse is typically real.

In a 19-litre body of water, chemical modifications happen 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 specifications (temperature level and pH) fluctuate more quickly.

For that reason, running a successful 19-litre aquarium needs diligence, steady regimens, and a trustworthy water screening kit.

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

Since of the restricted volume, stocking a 19-litre tank needs careful preparation. You can not keep large fish, nor can you keep education fish that require long swimming areas.

Here is what can conveniently live in a 5-gallon/ 19-litre tank:

A Single Betta Fish (Siamese Fighting Fish): A 19-litre tank is commonly considered the gold standard minimum size for a single male or female Betta. It offers them enough room to explore, especially if planted largely.
Freshwater Shrimp: Cherry shrimp, Amano shrimp, and crystal shrimp thrive in nano tanks. You can comfortably 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 wonderful clean-up crews. A single nerite snail will help keep algae under control.
Nano Fish Species: Very couple of fish types are appropriate for a tank this size. Endler's livebearers (males just, to prevent overbreeding) or Microdevario kubotai (emerald dwarf rasbora) can work, but only if the aquarist is knowledgeable and preserves rigorous water quality.

What NOT to Put in a 19-Litre Tank

To guarantee animal welfare, avoid keeping the following types in a 5-gallon aquarium:

Goldfish: Goldfish produce huge amounts of waste and grow far too large. They require a minimum of 75+ litres for a single elegant goldfish.
Tetras, Danios, or Barbs: These are schooling fish. To be happy, they require to be kept in groups of six or more and need horizontal swimming space (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. Important Equipment for a 19-Litre Tank

Establishing an 18.9-litre aquarium requires particular gear reduced to nano proportions.

Filtering: You will require a small, adjustable hang-on-back (HOB) filter or a sponge filter rated for approximately 20 or 30 litres. Make sure the circulation rate isn't too strong, as fish like Bettas struggle against heavy currents.
Heating unit: Most exotic fish require a stable temperature level in between 24 ° C and 26 ° C(75 ° F— 78 ° F ). A small 25-watt submersible heater is typically sufficient for a 19-litre volume.
Lighting: Simple LED lights are perfect. If you wish to grow live plants (like Anubias, Java Fern, or Bucephalandra), make sure the light has a spectrum suited for plant growth.
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 all set to bring your 5-gallon tank to life, follow this fundamental setup outline:

Rinse and Position: Place your tank on a durable, level surface area far from direct sunshine (to avoid algae blossoms). Wash the glass with warm water— never use soap or chemicals.
Include Substrate: Add 2 to 4 kgs of aquarium gravel or nutrient-rich aqua-soil, sloping it a little toward the back for visual depth.
Install Hardscape & & Plants: Arrange driftwood, rocks, and live or silk plants. Live plants assist absorb nitrates and stabilize 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 troubling your substrate design.
Include Water Conditioner: Treat the faucet water with a dechlorinator to eliminate harmful chlorine and chloramines.
Set up Equipment: Set up your filter and heater, then plug them in.
The Nitrogen Cycle: Crucial Step. Allow the tank to cycle for 2 to 4 weeks before including any fish. This constructs up useful germs 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/ pounds)

Water Capacity

~ 18.9 Litres

5 United States Gallons

Total Weight (Full)

~ 20— 22 kg

~ 44— 48 pounds

Normal 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

Understanding that a 5-gallon aquarium translates to 18.9 litres is the primary step towards building a flourishing water environment. While compact and ideal for tight spaces, a 19-litre tank demands respect, patience, and routine maintenance. By equipping it responsibly— maybe with a magnificent Betta fish or a colony of colorful freshwater shrimp— you can develop a spectacular, dynamic slice of nature right on your desktop.