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125 Gallon Aquarium Dimensions, Buyer’s Guide & Tips

An aquarium is a fail-safe idea to liven up your living room or infuse some positive energy in your office space.

If the space in your home or office allows it, you can try keeping a 125-gallon aquarium there. It will not only give ample space to your fish for a swim, but it will also become the centerpiece of the room.

When planned well and filled with the right fish and aquarium decorations, a 125-gallon fish tank can make a great addition to your house.

It might seem a little daunting at first to keep an aquarium this size clean, but due to its large size, you may not have to clean it as frequently as a small aquarium.

125 Gallon Aquarium Dimensions

The standard 125-gallon tank dimensions are 72” by 18” by 21”.

It does cost more than your regular size aquarium, but its beauty is worth the price.

Why should you go for a 125-Gallon Fish Tank?

A 125-gallon aquarium stands out in a room but maintaining it is not something recommended for amateur aquarists. Breeders and fish enthusiasts are people who would love to handle 125-gallon aquarium.

A large aquarium allows you to keep fish that can grow as big as 14 inches and still swim around with ease in the aquarium.

It will enable you to unleash your creativity and play around with various themes. You can do the aquascaping of such aquariums beautifully.

A 125-gallon fish tank is generally preferred by aquarists who want to expand their fish collection or give a better and more spacious home to their existing collection. When fish get ample unhindered space to swim, it helps in their growth.

In an aquarium this size, you can have many medium-sized and even large fish along with an extensive collection of plants and reefs without compromising on the space. You get to enjoy seeing the fish swim and enjoy the beauty of the fish tank.

The number of fish you can keep in a 125-gallon aquarium depends on the kind of aquarium you maintain.

While freshwater fish prefer to stay in schools and saltwater fish are territorial and like open spaces.

When you do the aquascaping of a large fish tank, you can have an elaborate theme of your choice, complete with background, aeration toys, and other aquarium decorations.

An aquarium this size requires commitment, knowledge, time, and patience in keeping it clean and maintaining its aesthetics.

3 Best 125 Gallon Aquariums

Aqueon 125-Gallon LED Aquarium

Aqueon 125-gallon aquarium

The Aqueon 125-gallon aquarium in Glass comes with an ensemble stand in black and grey colors. You also get a glass canopy and 2 LED strip lights with this aquarium. Can turn these LED lights on and off with a simple switch.

The glass canopy protects the fish and keeps them from jumping out. It is perfect for goldfish and tropical fish, and you can go in for a large assortment of fish of your choice with an aquarium this big.

The wooden stand that accompanies the aquarium can be used to keep your fish tank supplies like extra accessories and food. Since this Aqueon fish tank weighs a lot, this stand also provides good support for its weight.

The dimensions of this tank are 72.5″ L x 18.5″ W x 23.4″ H (184.2 L x 47.0 W x 59.4 H cm) and the 125-gallon aquarium stand measures 74.0″ L x 21.0″ W x 30.6″ H (188.0 L x 53.3 W x 77.7 H cm).

The accessories needed in a fish tank are not included, so you need to arrange for them separately. The bigger the fish tank, the more accessories you need, and the more expensive it gets as a whole


  • Reasonably priced for its size
  • The LED lights can be placed individually, and you do not need to replace all of them together


  • LED lights are only for display and do not provide any support to the plants or corals
  • Accessories not included

Marineland Corner-Flo Black Rectangular Aquarium

Maineland 125-gallon aquarium

This 125-gallon aquarium is perfect for saltwater and freshwater fish. It is compatible with most varieties and brands of lighting, filters, and sumps

It can quickly remove The front section of this fish tank to clean it, which is a great plus. This aquarium has a silicon-sealed top frame that prevents any capillary action.

This fish tank is ideal for anyone who is looking for an aquarium that is pre-drilled for filtration. Plastic frames support the top and bottom of this tank. It has been designed to provide maximum water flow to the filter.

A plumbing kit with bulkhead fittings, dual-outlet nozzles, drain, and return pipes is included with the aquarium. You might need additional plumbing accessories for any external filtration unit that you may attach to this aquarium.


  • Scratch-resistant and distortion-free
  • Most of the accessories are included


  • The aquarium hood and stand are not included with this aquarium.

ELOS System Diamond Line Aquarium

Elos 120 xl aquarium

This top-of-the-line aquarium is made from ELOS Diamond glass with polished edges that give it a seamless finish.

The dimensions of this tank are 47.24″ L x 31.50″ W x 19.70″ H (120 L x 80 W x 50 H cm). The square 120 xl stand of this aquarium has a water-resistant core and can also customize in finish and color, and finish.

Dimensions for this aquarium stand are 47.24″ L x 31.50″ W x 35.00″ H (120 L x 80 W x 89 H cm), and this creates an even balance for this tank.

The aquarium comes with a corrugated drain hose, red silicone return hose, Teflon tape, and PVC fittings.


  • Many accessories included
  • The Glass has a 98% clarity


  • Slightly expensive
  • Sump not included

While picking your aquarium, make sure you review the price, quality, and accessories included with the aquarium. It would help if you bought these fish tanks with stands that have been made as per the aquarium dimensions.

Things to Consider

Material: Glass or Acrylic

125-gallon aquariums come in glass and acrylic, and both materials are pretty sturdy when it comes to holding such a large quantity of water.

Let’s see the various parameters you must consider before making a choice.


One area where acrylic scores over glass are the weight since, for an aquarium this size, glass adds its significance along with the weight of water.

Acrylic, with its lighter weight, is a good choice for a 125-gallon fish tank. It is ten times lighter than glass, and redecorating or moving the aquarium becomes more accessible with the lighter weight.

The glass aquarium, along with the weight of the water, becomes too heavy and very difficult to handle.

The weight of 125 gallons of water is 1042.5 lbs (472.9 kg), and an empty 125-gallon aquarium weighs about 200 pounds (90.7 kg).

Add to it the weight of the substrate, rocks, decorations, filtrations, and the other aquarium equipment, and it would easily weigh close to 2000 pounds (907.2 kg)!


Acrylic also scores higher than glass when it comes to strength. Glass breaks or shatters easily. while acrylic does not. Large aquariums made out of acrylic are more resilient and do not chip easily.

However, acrylic does tend to get scratched if you use vital algae brush to clean the aquarium walls.


Glass aquariums in this size are rectangular as you cannot customize glass to take the shape of your choice.

On the other hand, acrylic is not as brittle and hard as glass and can be easily shaped. You can get your aquarium shaped as per your choice in these aquarium dimensions with acrylic.


A glass aquarium with curved edges tends to bend light at these edges, making the fish appear smaller or bigger than they are.

We feel that acrylic is suitable for aquarists who are DIY enthusiasts, while glass aquarium is perfect for beginners.