125 gallon tank: size, liters and setup numbers
The 125 gallon is a 6 foot tank for big schools and larger fish. Filled, it is very heavy, so check that your floor and stand can carry the load before setting it up.
| Typical dimensions | 72 × 18 × 21 in 182.9 × 45.7 × 53.3 cm |
|---|---|
| Volume | 125 US gallons 473.2 liters |
| Realistic water after substrate and decor | About 106.2 gal About 402.2 L |
| Water weight | About 1,042 lb About 473 kg |
| Gravel for a 1 inch bed | About 75 lb About 34 kg |
| Gravel for a 2 inch bed | About 150 lb About 68 kg |
| Heater (room 8°F / 4.4°C cooler) | 2 × 150 W |
| Heater (room 15°F / 8.3°C cooler) | 2 × 300 W |
| Filter flow (4 to 6 times per hour) | 500 to 750 GPH 1,893 to 2,839 L/h |
Dimensions vary a little between brands. For exact numbers, measure your tank and use the calculators below.
Plan the rest of your 125 gallon tank
Common questions
- How many liters is a 125 gallon tank?
- A 125 gallon tank holds about 473.2 liters when filled to the brim. With substrate and decorations, the real water volume is usually closer to 402 liters.
- How much does a 125 gallon tank weigh when full?
- The water alone weighs about 1,042 pounds (473 kg). Glass, substrate and rock add more on top, so choose a stand rated for the full weight.
- What size heater does a 125 gallon tank need?
- If your room stays around 8°F below your target water temperature, a 2 × 150 W heater is a good fit. For colder rooms, around 15°F below target, go with 2 × 300 W.