55 gallon fish tank: dimensions, weight & setup
A standard 55 gallon tank measures 48 × 13 × 21 inches, holds about 50.8 gallons of real water and weighs roughly 545 lb once set up. It is a great size for large communities, angelfish groups and Lake Malawi cichlids.
55 Gallon tank dimensions
| Inches | Centimeters | |
|---|---|---|
| Length | 48 in | 121.9 cm |
| Width (front to back) | 13 in | 33.0 cm |
| Height | 21 in | 53.3 cm |
| Footprint | 624 in² (4.3 ft²) | 4,026 cm² |
| Typical glass | 1/4 in | 6 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 | 56.7 | 214.7 |
| Filled 1 in below the rim | 50.8 | 192.2 |
| With 2 in of gravel | 45.6 | 172.7 |
Dose medication and fertilizer for the real water — about 46 gallons once the tank is aquascaped, not 57.
How much does a 55 gallon tank weigh?
| Empty (estimated, 1/4 in glass) | 79 lb | 36 kg |
|---|---|---|
| Filled with fresh water | 503 lb | 228 kg |
| Set up, fresh water + 2 in gravel | 544 lb | 247 kg |
| Set up as saltwater | 553 lb | 251 kg |
| Floor load under the stand | 125 lb/ft² | 6.0 kPa |
Add rock, decor and the stand (often 40–120 lb). A floor load of 125 lb/ft² is 3.1× 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) | 2 × 50 W |
| 68 °F (10 °F lift) | 2 × 100 W |
| 63 °F (15 °F lift) | 2 × 150 W |
Colder room, nano heater or dual-heater setup? See the 55 gallon heater size chart.
Plan maintenance with the water change schedule: a 30% change on this tank is about 13.7 gallons.
Filter flow
| Tank type | Real flow | Filter rating |
|---|---|---|
| Community tropical | 203–305 GPH | 290–435 GPH |
| Planted tank | 254–406 GPH | 363–580 GPH |
| Goldfish, cichlids or heavy feeders | 406–508 GPH | 580–725 GPH |
Substrate
| Depth | Gravel | Sand |
|---|---|---|
| 1 in (2.5 cm) | 34 lb | 33 lb |
| 2 in (5.1 cm) | 69 lb | 66 lb |
| 3 in (7.6 cm) | 103 lb | 100 lb |
Stocking ideas
- 4 angelfish + 8 bronze corydoras + 1 bristlenose pleco (no small tetras)
- 15 rummy-nose tetras + 8 corydoras + 2 pearl gouramis + 1 bristlenose pleco
- Species tank of 8 yellow lab cichlids with rockwork and hard water
Check any combination — including temperature and group size — in the stocking calculator.
Setup tips
- The classic 48 × 13 × 21 inch size is narrow and tall: great for angelfish, harder for aquascaping and reaching the bottom.
- Set-up weight passes 500 lb — use a purpose-built stand and place it across the floor joists.
- Two heaters of about 100 W each heat more evenly than one 200 W heater.
FAQ
What are the dimensions of a 55 gallon fish tank?
A standard 55 gallon glass tank measures 48 × 13 × 21 inches (121.9 × 33.0 × 53.3 cm) on the outside, a footprint of 4.3 square feet. Brands differ by up to about half an inch.
How much does a 55 gallon fish tank weigh?
About 80 lb empty, 505 lb filled with water and roughly 545 lb set up with 2 inches of gravel, before rock, decor and the stand.
How many gallons does a 55 gallon tank really hold?
56.7 gallons by its outside dimensions, about 50.8 gallons (192 liters) filled an inch below the rim, and about 45.6 gallons with 2 inches of gravel.
What size heater does a 55 gallon tank need?
2 × 100 W to hold 78 °F in a 68 °F room; 2 × 50 W in a 73 °F room and 2 × 150 W in a 63 °F room.
How much gravel or sand for a 55 gallon tank?
About 34 lb of gravel per inch of depth: 69 lb for a 2-inch bed, or 66 lb of sand.
What filter flow does a 55 gallon tank need?
203–305 GPH of real flow for a community tank (4–6× turnover), so choose a filter rated about 290–435 GPH.