How much substrate do I need for a 5 gallon tank?

For a 41 x 20 cm footprint at a 3 inch average depth you need about 6 litres: roughly 6 kg of aqua soil or 9 kg of sand. At 2 inches it is 4 litres.

What size heater for a 5 gallon planted tank?

A 25 W heater. Once substrate and rock are in, a 5 gallon holds about 14 litres (3.7 gallons) of water, which works out to 6.7 W per gallon.

How much filter flow does a 5 gallon planted tank need?

Aim for 60-80 litres per hour, which turns the water over 4 to 6 times an hour. Planted tanks like steady, gentle flow rather than a jet.

Is a 5 gallon tank big enough for live plants?

Yes. Low-light plants like moss, anubias and crypts grow well in 5 gallons with a small LED and no CO2. The limit is stability, not space: do 30% water changes weekly.

5 gallon planted tank setup

The classic desk nano. Small enough to light with one clip-on or a 40 cm bar, big enough for a shrimp colony and a carpet.

Dimensions: 41x20x25 cm; 16 x 8 x 10 in outer
Water volume: 14 L; 21 L (5.5 gal) gross, less substrate and rock
Substrate, 3 in average: 6 L; 6 kg aqua soil or 9 kg sand
Heater: 25 W; 6.7 W per gallon
Filter flow: 60-80; litres per hour, 4-6x turnover
Light timer: 6-7 hours; without CO2

Lighting

A 41 cm tank needs a bar that covers the full length so the ends do not go dark.

Fits this tank

RGBW 55 Full Spectrum LED

40 cm bar, brackets reach 55 cm; your tank is 41 cm long.

$66

Filtration

Target 60-80 L/h. In a tank this small a gentle filter beats a strong one.

Right-sized filter

Nano Hang-On Filter — USB Powered

Low flow sized for nano tanks; will not batter shrimp or a betta.

$18

CO2

Not needed. Pick low-light plants, keep the light on a 6-7 hour timer, and dose a little liquid fertilizer weekly.

Substrate by depth

Slope it: shallower at the front glass, deeper at the back. The average depth is what sets how much you buy.

2 in average

4 L

4 kg soil, 6 kg sand

3 in average

6 L

6 kg soil, 9 kg sand

4 in average

8 L

8 kg soil, 13 kg sand

Custom tank? Use the substrate calculator

What to plant

Suits: Nano shrimp tank or a single betta with a moss and crypt scape.

Java moss and Christmas moss on wood
Cryptocoryne parva or wendtii in the foreground
Anubias nana petite tied to stone
Monte Carlo if you add DIY CO2

Fish and shrimp

A colony of neocaridina shrimp, or one betta, or a small group of chili rasboras. Not all three: 19 litres crashes fast when you overstock it.

Mistakes that cost people this tank

1Heater too big. A 25 W unit is plenty; anything larger cooks a tank this small if the thermostat sticks.
2Too much flow. Bettas and shrimp both hate a waterfall filter on full; a USB nano filter or sponge is the right size.
3Dosing by the cap. Liquid fertilizer dose charts assume 40 L or more, so measure in drops, not caps.

Quick answers

How much substrate do I need for a 5 gallon tank?: For a 41 x 20 cm footprint at a 3 inch average depth you need about 6 litres: roughly 6 kg of aqua soil or 9 kg of sand. At 2 inches it is 4 litres.
What size heater for a 5 gallon planted tank?: A 25 W heater. Once substrate and rock are in, a 5 gallon holds about 14 litres (3.7 gallons) of water, which works out to 6.7 W per gallon.
How much filter flow does a 5 gallon planted tank need?: Aim for 60-80 litres per hour, which turns the water over 4 to 6 times an hour. Planted tanks like steady, gentle flow rather than a jet.
Is a 5 gallon tank big enough for live plants?: Yes. Low-light plants like moss, anubias and crypts grow well in 5 gallons with a small LED and no CO2. The limit is stability, not space: do 30% water changes weekly.