29 Gallon Tank Dimensions: Size, Weight and Stand

A standard 29 gallon tank is about 2 1/2 feet long, 1 foot deep and 1 1/2 feet tall. Aqueon lists its 29 at 30 1/4 x 12 1/2 x 18 3/4 inches (76.8 x 31.8 x 47.6 cm) outside, 40 lb empty and about 330 lb filled. It sits on the same 30 x 12 inch footprint as a 20 gallon long, just 6 inches taller, which is why it is one of the most common first upgrades.

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29 Gallon Tank Specs

Source: Aqueon product catalog, "Critical dimensions for all aquariums", checked November 2026: aqueon.com. Metric values, footprint and UK gallons calculated by FishyKart. Other brands differ by a fraction of an inch.

Real Water Volume

The outside dimensions multiply out to 30.7 gallons gross because they include the glass and frame. With a 2 inch gravel bed and the water 1 inch below the rim, a 29 gallon holds about 26 gallons (98 liters) of water. Dose conditioner and medication for that amount; a 25% water change is about 6 1/2 gallons. To check your own setup, use the aquarium volume calculator.

Weight and Stand

At about 8.3 lb per gallon (derived from the USGS water density table), 29 gallons of water weigh about 242 lb. With 40 lb of glass and typical gravel and decor, Aqueon puts the filled tank at 330 lb.

That weight sits on a narrow 2.63 square foot base, about 126 lb per square foot, more concentrated than a 40 breeder (about 100 lb per square foot). Most household furniture is not built for 330 lb on a 30 inch top, so use a stand made for a 29 or 20 long (30 x 12 inch top), place it on a level floor against a wall, and keep it away from soft carpet that lets one corner sink. This is general information, not a structural assessment.

29 Gallon vs 20 Long, 30 and 40 Breeder

Dimensions and weights: Aqueon "Critical dimensions" table. Footprints calculated by FishyKart.

• 29 vs 20 long: same footprint and stand, 6 inches taller. You gain about 9 gallons of water and room for taller plants and fish like angelfish juveniles, but no extra floor space for bottom dwellers.
• 29 vs 30: nearly the same water, very different shape. The 30 is 6 inches longer and 2 inches shorter, with 21% more floor area, which suits active schooling fish better.
• 29 vs 40 breeder: the 40 breeder is 6 inches longer, almost 6 inches deeper and has 75% more floor area. It is the usual next step when a 29 gets crowded.

What Fits in a 29 Gallon

The 29 is a classic community tank. From our care guides:

• Small schooling fish: two schools, such as neon tetras plus rummy nose or harlequin rasboras, with a corydoras group and a bristlenose pleco.
• Bottom dwellers: 7 to 8 kuhli loaches, or 8 to 10 otocinclus as the cleanup crew.
• Livebearers: a good all-round size for a molly group; it is the smallest practical tank for a few sailfin mollies.
• Not for adults of: angelfish (18 inches of height is fine for juveniles, cramped for adults), oscars, large cichlids and fancy goldfish groups, which need a 40 breeder or bigger.

Before You Buy a 29

• Lids, lights and backgrounds for a 20 long fit the 29: both are 30 x 12 inches.
• The tank is 18 3/4 inches tall: on a high stand, check you can reach the bottom for gravel cleaning.
• A 30 x 12 inch stand rated for a 29 also works for a 20 long, so it keeps your options open.
• Empty the tank completely before moving it, even a few inches.

Related Guides

• Aquarium Volume Calculator and Size Chart
• 40 Gallon Tank Dimensions: Breeder vs Long
• Neon Tetra Tank Mates
• Kuhli Loach Tank Size