2.5 gallon fish tank size and measurements
How big is a 2.5 gallon tank? It is about 1.0 feet long (12 in), 6 inches from front to back and 8 inches tall, so it needs a stand or space at least 12 x 6 inches.
- Outside dimensions
- 12 x 6 x 8 in30.5 x 15.2 x 20.3 cm
- Volume
- 2.5 US gal9 L, 2 UK gal
- Footprint
- 0.5 sq ft72 sq in
- Water weight
- 21 lb9 kg
Checked against the manufacturer's specs: the Aqueon 2.5 gallon measures 12 3/16 x 6 1/8 x 8 1/8 in outside, 2.6 lb empty. The size above is the rounded standard size most charts use.
Measured from the outside, these dimensions hold about 2.5 US gallons. Real water volume is lower because of glass thickness, substrate, decor and the gap below the rim. Check the real figure with the aquarium volume calculator.
How much does a 2.5 gallon tank weigh?
A 2.5 gallon tank weighs about 32 lb (15 kg) once set up, counting the empty glass (3 lb), the water and 2 inches of gravel. Use a stand rated for the full weight, on a level floor. The fish tank weight guide compares every size.
How much gravel or sand for a 2.5 gallon tank?
| Bed depth | Gravel | Sand | Aquasoil |
|---|---|---|---|
| 1 in (2.5 cm) | 4 lb | 4 lb | 1 L |
| 2 in (5.1 cm) | 8 lb | 8 lb | 2 L |
| 3 in (7.6 cm) | 12 lb | 12 lb | 4 L |
Based on a 12 x 6 in floor and typical bulk densities.
Different depth? Use the aquarium substrate calculator.
Heater and filter size for a 2.5 gallon tank
A common rule is 3–5 watts per gallon, so a 2.5 gallon tank needs about 7.5–12.5 W: one 25 W heater suits most rooms. Use the higher end in cold rooms.
For filtration, aim to turn the water over 4–6 times an hour: a filter rated around 10.0–15.0 gallons per hour.
Fish that suit a 2.5 gallon tank
- A small colony of cherry shrimp
- Nerite or ramshorn snails
- Mosses and small plants such as anubias nana
- A spare tank for raising shrimp or plants
Starting ideas only. Check each species' adult size, temperament and water needs before buying.
Compare nearby sizes
- Next larger: 5 gallon, 16 x 8 x 10 in
See every size in the aquarium size chart.
Frequently asked questions
What are the dimensions of a 2.5 gallon tank?
A standard 2.5 gallon aquarium measures about 12 x 6 x 8 inches (30.5 x 15.2 x 20.3 cm), length x width x height. Brands vary by a fraction of an inch.
How long is a 2.5 gallon tank?
About 12 inches (30.5 cm), or 1.0 feet.
How big is a 2.5 gallon tank?
It is about 1.0 feet long, 6 inches deep and 8 inches tall, and takes up 0.5 square feet of floor.
How much does a 2.5 gallon tank weigh when full?
About 32 lb (15 kg) once set up, counting the empty glass (3 lb), the water and 2 inches of gravel.
How much gravel do I need for a 2.5 gallon tank?
For a 2 inch bed, about 8 lb of gravel or 8 lb of sand.
What size heater does a 2.5 gallon tank need?
About 7.5–12.5 watts in total, so one 25 W heater suits most rooms.
Last updated .