75 gallon fish tank: dimensions, weight & setup
A standard 75 gallon tank measures 48 × 18 × 21 inches, holds about 69.2 gallons of real water and weighs roughly 770 lb once set up. It is a great size for oscars, mbuna, big communities and reef tanks — the most popular large tank.
75 Gallon tank dimensions
| Inches | Centimeters | |
|---|---|---|
| Length | 48 in | 121.9 cm |
| Width (front to back) | 18 in | 45.7 cm |
| Height | 21 in | 53.3 cm |
| Footprint | 864 in² (6.0 ft²) | 5,574 cm² |
| Typical glass | 3/8 in | 10 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 | 78.5 | 297.3 |
| Filled 1 in below the rim | 69.2 | 262.1 |
| With 2 in of gravel | 62.2 | 235.4 |
Dose medication and fertilizer for the real water — about 62 gallons once the tank is aquascaped, not 79.
How much does a 75 gallon tank weigh?
| Empty (estimated, 3/8 in glass) | 135 lb | 61 kg |
|---|---|---|
| Filled with fresh water | 713 lb | 324 kg |
| Set up, fresh water + 2 in gravel | 769 lb | 349 kg |
| Set up as saltwater | 782 lb | 355 kg |
| Floor load under the stand | 128 lb/ft² | 6.1 kPa |
Add rock, decor and the stand (often 40–120 lb). A floor load of 128 lb/ft² is 3.2× 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 × 75 W |
| 68 °F (10 °F lift) | 2 × 150 W |
| 63 °F (15 °F lift) | 2 × 200 W |
Colder room, nano heater or dual-heater setup? See the 75 gallon heater size chart.
Plan maintenance with the water change schedule: a 30% change on this tank is about 18.7 gallons.
Filter flow
| Tank type | Real flow | Filter rating |
|---|---|---|
| Community tropical | 277–415 GPH | 396–594 GPH |
| Planted tank | 346–554 GPH | 495–791 GPH |
| Goldfish, cichlids or heavy feeders | 554–692 GPH | 791–989 GPH |
Substrate
| Depth | Gravel | Sand |
|---|---|---|
| 1 in (2.5 cm) | 47 lb | 46 lb |
| 2 in (5.1 cm) | 94 lb | 91 lb |
| 3 in (7.6 cm) | 141 lb | 137 lb |
Stocking ideas
- 1 oscar with heavy filtration (species-only)
- 10 yellow lab cichlids in a rocky Lake Malawi layout
- 5 angelfish + 10 bronze corydoras + 1 bristlenose pleco
Check any combination — including temperature and group size — in the stocking calculator.
Setup tips
- Same length as a 55 but 18 inches deep — far better for aquascaping and territorial fish.
- Set-up weight is around 770 lb before rock and stand: put it on a ground floor or close to a load-bearing wall.
- Two 150 W heaters and a canister or sump filter rated around 400–700 GPH are typical.
FAQ
What are the dimensions of a 75 gallon fish tank?
A standard 75 gallon glass tank measures 48 × 18 × 21 inches (121.9 × 45.7 × 53.3 cm) on the outside, a footprint of 6.0 square feet. Brands differ by up to about half an inch.
How much does a 75 gallon fish tank weigh?
About 135 lb empty, 715 lb filled with water and roughly 770 lb set up with 2 inches of gravel, before rock, decor and the stand.
How many gallons does a 75 gallon tank really hold?
78.5 gallons by its outside dimensions, about 69.2 gallons (262 liters) filled an inch below the rim, and about 62.2 gallons with 2 inches of gravel.
What size heater does a 75 gallon tank need?
2 × 150 W to hold 78 °F in a 68 °F room; 2 × 75 W in a 73 °F room and 2 × 200 W in a 63 °F room.
How much gravel or sand for a 75 gallon tank?
About 47 lb of gravel per inch of depth: 94 lb for a 2-inch bed, or 91 lb of sand.
What filter flow does a 75 gallon tank need?
277–415 GPH of real flow for a community tank (4–6× turnover), so choose a filter rated about 396–594 GPH.