5 gallon fish tank: dimensions, weight & setup
A standard 5 gallon tank measures 16 × 8 × 10 inches, holds about 4.7 gallons of real water and weighs roughly 55 lb once set up. It is a great size for a single betta, a cherry shrimp colony or a nano school of chili rasboras.
5 Gallon tank dimensions
| Inches | Centimeters | |
|---|---|---|
| Length | 16 in | 40.6 cm |
| Width (front to back) | 8 in | 20.3 cm |
| Height | 10 in | 25.4 cm |
| Footprint | 128 in² (0.9 ft²) | 826 cm² |
| Typical glass | 1/8 in | 3 mm |
These are typical outside dimensions for US glass tanks; brands vary slightly, so measure yours before buying a stand, lid or background.
How much water does it really hold?
| US gallons | Liters | |
|---|---|---|
| Outside dimensions | 5.5 | 21.0 |
| Filled 1 in below the rim | 4.7 | 17.8 |
| With 2 in of gravel | 3.6 | 13.8 |
Dose medication and fertilizer for the real water — about 4 gallons once the tank is aquascaped, not 6.
How much does a 5 gallon tank weigh?
| Empty (estimated, 1/8 in glass) | 8 lb | 3 kg |
|---|---|---|
| Filled with fresh water | 47 lb | 21 kg |
| Set up, fresh water + 2 in gravel | 55 lb | 25 kg |
| Set up as saltwater | 56 lb | 25 kg |
| Floor load under the stand | 62 lb/ft² | 3.0 kPa |
Add rock, decor and the stand (often 40–120 lb). A floor load of 62 lb/ft² is 1.5× the 40 lb/ft² a typical home floor is designed for when averaged over a room, so place the stand across the joists and near a load-bearing wall. Use the weight calculator to include your own rock and stand.
Heater size
| Room temperature (water at 78 °F) | Heater |
|---|---|
| 73 °F (5 °F lift) | 10 W |
| 68 °F (10 °F lift) | 25 W |
| 63 °F (15 °F lift) | 25 W |
Colder room, nano heater or dual-heater setup? See the 5 gallon heater size chart.
Plan maintenance with the water change schedule: a 30% change on this tank is about 1.1 gallons.
Filter flow
| Tank type | Real flow | Filter rating |
|---|---|---|
| Community tropical | 19–28 GPH | 27–40 GPH |
| Planted tank | 23–38 GPH | 33–54 GPH |
| Goldfish, cichlids or heavy feeders | 38–47 GPH | 54–67 GPH |
Substrate
| Depth | Gravel | Sand |
|---|---|---|
| 1 in (2.5 cm) | 7 lb | 7 lb |
| 2 in (5.1 cm) | 14 lb | 14 lb |
| 3 in (7.6 cm) | 21 lb | 21 lb |
Stocking ideas
- 1 male betta + 1 nerite snail
- 8 chili rasboras + a colony of cherry shrimp
- Cherry shrimp colony on moss with a sponge filter
Check any combination — including temperature and group size — in the stocking calculator.
Setup tips
- Small volumes swing in temperature and ammonia quickly — test water weekly and change 25–30%.
- Use a sponge filter or a hang-on-back filter with a baffled outflow; bettas and shrimp dislike strong current.
- A 25 W adjustable heater is enough in most rooms. Avoid unregulated "preset" nano heaters.
FAQ
What are the dimensions of a 5 gallon fish tank?
A standard 5 gallon glass tank measures 16 × 8 × 10 inches (40.6 × 20.3 × 25.4 cm) on the outside, a footprint of 0.9 square feet. Brands differ by up to about half an inch.
How much does a 5 gallon fish tank weigh?
About 10 lb empty, 45 lb filled with water and roughly 55 lb set up with 2 inches of gravel, before rock, decor and the stand.
How many gallons does a 5 gallon tank really hold?
5.5 gallons by its outside dimensions, about 4.7 gallons (18 liters) filled an inch below the rim, and about 3.6 gallons with 2 inches of gravel.
What size heater does a 5 gallon tank need?
25 W to hold 78 °F in a 68 °F room; 10 W in a 73 °F room and 25 W in a 63 °F room.
How much gravel or sand for a 5 gallon tank?
About 7 lb of gravel per inch of depth: 14 lb for a 2-inch bed, or 14 lb of sand.
What filter flow does a 5 gallon tank need?
19–28 GPH of real flow for a community tank (4–6× turnover), so choose a filter rated about 27–40 GPH.