A 29-gallon aquarium weighs between 250 and 350 pounds when filled with water

The exact weight depends on what you put inside it. An empty 29-gallon tank itself weighs 40 to 50 pounds, depending on the glass thickness and frame material. Water adds roughly 240 pounds (since one gallon of freshwater weighs 8.34 pounds). Gravel, rocks, decorations, and equipment push the total higher. Most people find their filled 29-gallon setup lands between 280 and 330 pounds.

This matters because you need to know whether your floor can handle it. A standard wooden floor in a house is built to support 40 pounds per square foot spread across the room. A 29-gallon tank sitting on a 2-foot-by-1-foot stand concentrates 250 to 350 pounds into 2 square feet, which is 125 to 175 pounds per square foot in that spot. Older homes, second floors, and apartments often cannot support this. Concrete basement floors have no problem. If you are unsure, place the tank against a wall where the weight transfers to the foundation, or ask a contractor to check your floor joists.

Key Takeaways

  • A filled 29-gallon aquarium typically weighs 250 to 350 pounds, with water making up about 240 of those pounds.
  • The empty glass tank itself weighs 40 to 50 pounds, and gravel or sand substrate adds another 20 to 50 pounds depending on depth and type.
  • Weight concentrates in a small footprint, so check whether your floor can handle 125 to 175 pounds per square foot before setting up the tank.
  • Placing the tank against a wall or on a basement floor distributes weight more safely than putting it in the middle of a room on an upper level.

Breaking down the weight: tank, water, and substrate

The glass tank itself is the lightest part. A standard 29-gallon aquarium measures roughly 30 inches long, 12 inches wide, and 18 inches tall. The glass walls and bottom typically weigh 40 to 50 pounds. Tanks with thicker glass or reinforced frames (common in saltwater models) can reach 55 to 60 pounds empty. The stand or cabinet underneath adds another 30 to 80 pounds depending on whether it is a straightforward metal frame or a wooden cabinet with storage.

Water is the heavy part. Twenty-nine gallons of freshwater weighs about 242 pounds. Saltwater is slightly heavier at about 245 to 250 pounds because salt adds density. This is why the difference between a freshwater and saltwater setup is usually just a few pounds—the water itself is the dominant factor.

Substrate (gravel, sand, or rock on the bottom) adds significant weight. A 1-inch layer of standard aquarium gravel across a 29-gallon tank weighs roughly 20 to 25 pounds. A 2-inch layer weighs 40 to 50 pounds. Sand is slightly lighter per inch than gravel. If you use larger decorative rocks or driftwood, add another 10 to 30 pounds depending on how much you add.

How to measure your specific setup

If you want to know the exact weight of your tank before moving it, weigh it in stages. First, weigh the empty tank and stand together using a bathroom scale or a scale at a hardware store. Write down that number. Then fill the tank partway (to 6 inches) and weigh again. The difference tells you how much 6 inches of water weighs in your specific tank. Multiply that by 3 to estimate the full weight, then add back the weight of your substrate and decorations.

A simpler method: use the formula. Multiply the tank volume (29 gallons) by 8.34 pounds per gallon for freshwater, which gives you 242 pounds of water. Add 45 pounds for the empty tank and stand, then add the weight of your substrate. For most 29-gallon setups with 1 to 2 inches of gravel and a few decorations, expect a total between 300 and 330 pounds.

Floor safety and placement

Residential floors are engineered to support a distributed load of 40 pounds per square foot. A 29-gallon tank on a typical 24-by-12-inch stand creates a point load of roughly 150 pounds per square foot. This is safe on concrete, but risky on upper floors of older homes or in apartments built before 1980.

The safest placement is against an exterior wall on the ground floor or basement. The wall studs and foundation carry the weight directly downward. If you must place the tank on an upper floor, position it perpendicular to the floor joists (which run the length of the room) so the weight spreads across multiple joists instead of concentrating on one. Never place a 29-gallon tank in the center of a room on a second floor unless you have had a structural engineer confirm the floor can handle it.

If you live in an apartment, check your lease and contact the landlord or building management before setting up a 29-gallon tank. Many leases restrict aquariums over 20 gallons because of water damage risk and weight concerns.

Weight differences between tank styles

A standard rectangular 29-gallon tank (the most common type) weighs what we have described. Bow-front tanks (curved glass on the front) are slightly heavier because the curved glass is thicker. A bow-front 29-gallon tank can weigh 55 to 65 pounds empty instead of 40 to 50. Corner tanks and hexagonal tanks have different footprints but similar total weights when filled.

Acrylic tanks are lighter than glass. A 29-gallon acrylic tank weighs about 25 to 35 pounds empty, roughly half the weight of glass. However, acrylic scratches more easily and can cloud over time, so most aquarists stick with glass for a 29-gallon setup.

Moving and transporting a 29-gallon tank

Never move a 29-gallon tank while it is full. Drain it completely, remove the substrate, and take out decorations. Transport the empty tank and stand separately if possible. Even empty, a 29-gallon tank is awkward to carry because of its size and shape. Two people should handle it, with one person supporting each long side. Do not lift from the top frame alone—the glass can shift and crack.

If you are moving the tank to a new location in your home, drain it, move the stand first, then move the tank. Set the tank on the stand and refill slowly, checking for leaks as the water level rises. If the tank was sealed properly, it should not leak, but the pressure of refilling sometimes reveals small cracks that were not visible when empty.

Frequently Asked Questions

Can I put a 29-gallon tank on a plastic stand instead of wood?

Metal and plastic stands rated for aquariums can hold a 29-gallon tank, but check the weight rating on the stand itself. Most aquarium stands are rated for 300 to 400 pounds. A plastic storage shelf or folding table is not designed for this weight and will sag or collapse. Always use a stand made for aquariums.

Does the type of gravel affect how much the tank weighs?

Yes, slightly. Standard aquarium gravel weighs about 1.5 pounds per liter. Larger river rocks weigh more. Fine sand weighs less per volume. The difference is usually 5 to 10 pounds across the whole substrate layer, so it does not change the overall weight calculation much. Avoid using regular dirt or outdoor soil—it is heavier and will cloud your water.

What if I use a sump or external filter—does that add to the weight I need to support?

The sump sits under or beside the tank, not on top of it, so it does not add to the floor load directly under the tank. However, the sump itself holds water and adds weight to that spot on the floor. A 20-gallon sump weighs about 170 pounds when full. Plan for the sump to sit on its own sturdy stand in a location that can handle the weight.

Is a 29-gallon tank safe on a second-floor apartment?

It depends on the building. Modern apartments built after 1990 are usually fine. Older buildings may not be. Contact your landlord or building management before setting up the tank. Many will require written permission and may ask you to carry renter's insurance that covers water damage. Some buildings prohibit tanks over 20 gallons entirely.

How much does the water weigh if I use saltwater instead of freshwater?

Saltwater weighs about 3 to 8 pounds more than freshwater in a 29-gallon tank, depending on the salinity. For practical purposes, assume 245 to 250 pounds of saltwater instead of 242 pounds of freshwater. This small difference does not change whether your floor can support the tank—if freshwater is safe, saltwater is safe.