5 gallon Aquarium
Everything about the 5 gallon tank: its real water volume, the fish that fit, and the heater, filter, substrate, and total weight it needs — calculated with the same tools as our calculators.
Quick Facts
- Nominal Volume
- 5 US gallons (18.93 L)
- Approximate Water Volume
- 5–5 gallons
- Common Dimensions
- 16 × 8 × 10 inches
- Suitable Fish
- 6 species in our database
- Recommended Heater
- 25 W
- Recommended Filter
- 20 GPH (76 LPH)
Suitable Fish
These species have a minimum tank requirement of 5 gallons or less, so they can live in a 5 gallon tank:
Stocking Examples
A balanced starting point for a 5 gallon community — 10 × Cherry Shrimp + 1 × Nerite Snail.
Stocking status: Moderate — Bioload 3 of ~5 points for your 5-gallon tank.
Build your own planFilter Recommendations
For a freshwater community, target about 20 GPH (76 LPH) of actual turnover. The minimum sensible flow is 15 GPH.
Manufacturer flow is rated on an empty filter — real flow drops with media and head height, so choose toward the upper end.
Heater Requirements
Holding 78°F in a 68°F room needs roughly 25 W. A temperature rise of 10°F (5.6°C) is assumed.
Two smaller heaters (one at each end) heat more evenly and give redundancy — worth considering for larger tanks.
Substrate Amount
With a 2-inch gravel bed, a 5 gallon tank needs about 4.2 L / 256 cu in — roughly 7.05 kg / 15.54 lb.
Estimated Weight
Set up and filled, a 5 gallon tank weighs around 66.64 lb — including water, glass, a 2-inch gravel bed, and a small allowance for decor and equipment.
Add the stand or cabinet weight separately when checking your floor.
Compatible Equipment
- Heater: 25 W (adjust for your room temperature).
- Filter: 20 GPH (76 LPH) actual turnover.
- Substrate: 4.2 L / 256 cu in of gravel at a 2-inch depth.
- Lighting: match the fixture to the tank length (16 inches) and to your plants' needs.
- Stand: rated for at least 66.64 lb.
Frequently asked questions
How many gallons does a 5 gallon aquarium actually hold?
A 5 gallon tank is rated at 5 US gallons nominal, but real water volume runs lower — typically 5–5 gallons once it is filled to the frame line and you account for substrate, rock, and equipment displacement.
What fish can live in a 5 gallon tank?
Roughly 6 of the species in our database suit a 5 gallon tank (minimum tank requirement at or below 5 gallons). Popular options include Betta, Celestial Pearl Danio, Cherry Shrimp, Mystery Snail, Nerite Snail.
What filter do I need for a 5 gallon tank?
For a freshwater community, aim for about 20 GPH (76 LPH) of actual turnover — the minimum sensible flow is 15 GPH. Manufacturer ratings are measured on an empty filter, so size up when in doubt.
What heater wattage for a 5 gallon tank?
To hold 78°F in a 68°F room, a 5 gallon tank typically wants around 25 W. The exact figure depends on the temperature rise and how cold the room gets.
How much gravel does a 5 gallon tank need?
With a 2-inch bed, a 5 gallon tank needs about 4.2 L / 256 cu in, weighing roughly 7.05 kg / 15.54 lb.
Figures are planning estimates calculated at 68°F room → 78°F target, 90% fill, and a 2-inch gravel bed. Last reviewed: .