15 gallon fish tank: dimensions, weight & setup
A standard 15 gallon tank measures 24 × 12 × 12 inches, holds about 12.9 gallons of real water and weighs roughly 150 lb once set up. It is a great size for nano communities and planted betta tanks with a bit more room than a 10.
15 Gallon tank dimensions
| Inches | Centimeters | |
|---|---|---|
| Length | 24 in | 61.0 cm |
| Width (front to back) | 12 in | 30.5 cm |
| Height | 12 in | 30.5 cm |
| Footprint | 288 in² (2.0 ft²) | 1,858 cm² |
| Typical glass | 3/16 in | 5 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 | 15.0 | 56.6 |
| Filled 1 in below the rim | 12.9 | 48.7 |
| With 2 in of gravel | 10.5 | 39.7 |
Dose medication and fertilizer for the real water — about 10 gallons once the tank is aquascaped, not 15.
How much does a 15 gallon tank weigh?
| Empty (estimated, 3/16 in glass) | 21 lb | 10 kg |
|---|---|---|
| Filled with fresh water | 129 lb | 58 kg |
| Set up, fresh water + 2 in gravel | 148 lb | 67 kg |
| Set up as saltwater | 150 lb | 68 kg |
| Floor load under the stand | 74 lb/ft² | 3.5 kPa |
Add rock, decor and the stand (often 40–120 lb). A floor load of 74 lb/ft² is 1.8× 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) | 25 W |
| 68 °F (10 °F lift) | 50 W |
| 63 °F (15 °F lift) | 75 W |
See the heater size chart by tank or size your own in the heater calculator.
Plan maintenance with the water change schedule: a 30% change on this tank is about 3.1 gallons.
Filter flow
| Tank type | Real flow | Filter rating |
|---|---|---|
| Community tropical | 51–77 GPH | 73–110 GPH |
| Planted tank | 64–103 GPH | 92–147 GPH |
| Goldfish, cichlids or heavy feeders | 103–129 GPH | 147–184 GPH |
Substrate
| Depth | Gravel | Sand |
|---|---|---|
| 1 in (2.5 cm) | 16 lb | 15 lb |
| 2 in (5.1 cm) | 32 lb | 31 lb |
| 3 in (7.6 cm) | 48 lb | 46 lb |
Stocking ideas
- 8 harlequin rasboras + 6 pygmy corydoras + 1 honey gourami
- 1 betta + 8 chili rasboras + 3 amano shrimp
- 8 celestial pearl danios + cherry shrimp in a planted layout
Check any combination — including temperature and group size — in the stocking calculator.
Setup tips
- The 24 × 12 inch footprint matches a 20 high but at 12 inches tall it is far easier to reach and light for plants.
- Lids and lights for 24-inch tanks are widely available.
- Leave the back corners densely planted — nano fish color up when they have cover.
FAQ
What are the dimensions of a 15 gallon fish tank?
A standard 15 gallon glass tank measures 24 × 12 × 12 inches (61.0 × 30.5 × 30.5 cm) on the outside, a footprint of 2.0 square feet. Brands differ by up to about half an inch.
How much does a 15 gallon fish tank weigh?
About 20 lb empty, 130 lb filled with water and roughly 150 lb set up with 2 inches of gravel, before rock, decor and the stand.
How many gallons does a 15 gallon tank really hold?
15.0 gallons by its outside dimensions, about 12.9 gallons (49 liters) filled an inch below the rim, and about 10.5 gallons with 2 inches of gravel.
What size heater does a 15 gallon tank need?
50 W to hold 78 °F in a 68 °F room; 25 W in a 73 °F room and 75 W in a 63 °F room.
How much gravel or sand for a 15 gallon tank?
About 16 lb of gravel per inch of depth: 32 lb for a 2-inch bed, or 31 lb of sand.
What filter flow does a 15 gallon tank need?
51–77 GPH of real flow for a community tank (4–6× turnover), so choose a filter rated about 73–110 GPH.