In this article you will be able to choose the right dimensions of fish tank and their respective capacity with water.
From 2.5 gallons to more than 180 gallons, aquariums may be found in a variety of sizes. Depending on your goals and degree of expertise, you’ll be able to pick the best one for you.
Once filled with water, fish tanks may be very heavy, so it’s a good idea to know how much weight they will put on your table, cabinet, and even the floor.
The charts below detail the most common aquarium sizes, including size and empty weight information in U.S. units, as well as the weight when the tank is filled with water.
This is an important consideration, especially for larger tanks. Keep in mind that one gallon of water weighs 8.34 pounds, so you need to ensure that your cabinet and floor can handle the weight of your aquarium.
A 180-gallon aquarium, when filled with water, gravel, and accessories, weighs over 2,000 pounds.
This information will also help you guide several decisions, such as determining how much space is required, how much substrate and lighting you will need, recommended filter sizes, and other equipment needs.
Also, keep in mind that the surface area of the water in the tank will determine how many fish you can stock.
The weights given are for glass aquariums; acrylic aquariums will weigh somewhat less. Also, exact dimensions can vary by brand and the trim used on the aquarium.

To be more precise, it is best to take a tape measure with you to the fish store to get the exact measurements of your choice of the tank and double-check that all your accessories—particularly tank hoods and cabinets—fit properly.
It’s understandable that you’re curious about the size of a 20-gallon container, given that most are measured in gallons rather than inches or millimeters.
The dimensions of a 20-gallon fish tank are determined by the design, with some aquariums being longer than they are broad, and others being deeper (higher) than they are wide or long.
Still, most common 20-gallon size aquariums are either 24″ by 12″ by 16″ (high) or 30″ by 12″ by 12″ (long), with the numbers denoting the dimensions of the aquarium in terms of its length, breadth, and height.
Accordingly, the fish tank you purchase will be determined by the species you intend to maintain, the equipment you intend to utilize, and whether or not you intend to include live aquarium plants in the tank.
In addition, you should consider what kind of decorations you want to put in your aquarium and how many of them you want.
A longer aquarium is usually required for energetic, fast-swimming fish, rather than a taller aquarium in most cases.
Fish that prefer dim illumination, on the other hand, will fare better in a deeper tank since the light is more diluted before it reaches the fish.
Higher background plants will necessitate a larger aquarium, but a longer tank will suffice if you intend to include more carpet and foreground plants, which are often shorter.
Concerning the aquarium’s equipment, a longer aquarium is preferable if you want to include an air pump in the tank and have more space for a hanging filter.
Consider utilizing a canister filter in a larger 20-gallon fish tank, and especially in a larger tank if you want to add LED or energy-efficient grow lights, which have more light depth than standard grow lights.
10-gallon fish tanks are the most popular especially with the people new to fish keeping and choosing among the Different dimensions of fish tank.
Dimensions of Small Aquarium
It is not suggested for beginners to start with tiny aquariums, contrary to popular belief.
Due to the temperamental nature of these microscopic settings, even a little change in the chemistry of the water, such as an increase in ammonia or a decrease in pH, can have significant consequences.
If you do opt to retain a tiny fish tank, bear in mind that it will have a much lesser biofiltration capacity, thus it is critical that you do not overstock it with too many fish.
Aside from that, because it is such a delicate environment, effective filtration is very necessary for small tanks.
Tank Size | Length x Width x Height | Average Tank Weight with Water |
---|---|---|
2.5-gallon | 12″ x 6″ x 8″ | 30 lbs |
5-gallon | 16″ x 8″ x 10″ | 65 lbs |
10-gallon | 20″ x 10″ x 12″ | 120 lbs |
15-gallon | 24″ x 12″ x 12″ | 180 lbs |
15-gallon | 20″ x 10″ x 18″ | 180 lbs |
Dimensions of Medium sized Aquarium
For beginners, these are the aquariums that are most frequently suggested.
Generally speaking, anything in the 20 to 40 gallon range has adequate capacity to avoid adverse effects caused by chemical changes in the water while yet being large enough to accommodate a healthy population of fish.
Furthermore, because these tanks are not particularly huge, cleaning will not be a major challenge.
This is critical since many individuals who are new to aquariums quickly discover that keeping up with the necessary care becomes too much for them to handle. In general, the mid-sized tanks have a moderate size that is comfortable to work with.
20-gallon fish tanks are the most popular among the Different dimensions of fish tank.
Tank Size | Length x Width x Height | Fish tank Weight with water |
---|---|---|
20-gallon (high) | 24″ x 12″ x 16″ | 225 lbs |
20-gallon (long) | 30″ x 12″ x 12″ | 225 lbs |
25-gallon | 24″ x 12″ x 20″ | 282 lbs |
30-gallon (breeder) | 36″ x 18″ x 12″ | 348 lbs |
40-gallon | 36″ x 18″ x 16″ | 458 lbs |
Dimensions of a Large sized Aquarium
The more fish you can fit into an aquarium, the better. You will have to put in more effort to keep these tanks in good condition, which is a significant benefit.
In addition, when it comes to the weight of filled tanks of this site, you have to be cautious.
Making ensuring your floor and cabinet are capable of supporting such huge weights is essential.
Owners of really big tanks may even discover that floor reinforcement is required in order to handle a load in excess of one tonne in weight.
When it comes to aquarium design, larger tanks have a lot to offer, especially when it comes to creating a diversified aquarium.
However, you must also examine the tank’s overall size in relation to the space and its surroundings as a last point of consideration.
There is sufficient space between the tank and the wall for hoses and accessories. This appears to be a busy room.
Does the building have a limited amount of space, which might result in accidents or shattered glass?
Does your tank have any shelves that dangle over the edge that may fall and cause a commotion for your fish? Considering these considerations before making such a major commitment of your time and money is essential to your success.
50-gallon fish tanks are the most popular, especially with the people who are experienced and you can choose from the Different dimensions of fish tanks.
Large Aquariums | ||
---|---|---|
Tank Size | L x W x H | Filled Weight |
50-gallon | 36″ x 18″ x 19″ | 600 lbs. |
55-gallon | 48″ x 13″ x 21″ | 625 lbs. |
65-gallon | 36″ x 18″ x 24″ | 772 lbs. |
75 gallon | 48″ x 18″ x 21″ | 850 lbs. |
90-gallon | 48″ x 18″ x 24″ | 1050 lbs. |
125-gallon | 72″ x 18″ x 21″ | 1400 lbs. |
150-gallon | 72″ x 18″ x 28″ | 1800 lbs. |
180-gallon | 72″ x 24″ x 25″ | 2100 lbs. |
Choosing the right tank dimensions is very important and you will need to take care of different factors in order to do that.
Here are some of the different Dimensions of fish tanks you can consider to buy.
Number of gallons | Description | Approximate Dimension of fish tank (Width x Depth x Height) | Empty Tank Weight | Approximate Weight with water |
2.5 | 2.5 Gallon Rectangular Tank | 12″ x 6″ x 8″ | 3 lbs. | 23 lbs. |
5 | 5.5 Gallon Rectangular Tank | 16″ x 8″ x 10″ | 8 lbs. | 52 lbs. |
10 | 10 Gallon Rectangular Tank | 20″ x 10″ x 12″ | 11 lbs. | 91 lbs. |
10 | 10 Gallon Rectangular Tank | 20″ x 10″ x 12″ | 11 lbs. | 91 lbs. |
15 | 15 Gallon Rectangular Tank | 24″ x 12″ x 12″ | 22 lbs. | 142 lbs. |
16H | 16 Gallon High Rectangular Tank | 20″ x 10″ x 18″ | 24 lbs. | 152 lbs. |
20H | 20 Gallon High Rectangular Tank | 24″ x 12″ x 16″ | 27 lbs. | 187 lbs. |
20H | 20 Gallon High Rectangular Tank | 24″ x 12″ x 16″ | 27 lbs. | 187 lbs. |
20L | 20 Gallon Long Rectangular Tank | 30″ x 12″ x 12″ | 25 lbs. | 185 lbs. |
20L | 20 Gallon Long Rectangular Tank | 30″ x 12″ x 12″ | 25 lbs. | 185 lbs. |
20XH | 20 Gallon Extra-High Rect. Tank | 20″ x 10″ x 24″ | 29 lbs. | 189 lbs. |
25 | 25 Gallon Rectangular Tank | 24″ x12″ x20″ | 32 lbs. | 232 lbs. |
29 | 29 Gallon Rectangular Tank | 30″ x 12″ x 18″ | 39 lbs. | 270 lbs. |
29 | 29 Gallon Rectangular Tank | 30″ x 12″ x 18″ | 39 lbs. | 270 lbs. |
30 | 30 Gallon Rectangular Tank | 36″ x 13″ x 16″ | 41 lbs. | 281 lbs. |
30 | 30 Gallon Rectangular Tank | 36″ x 13″ x 16″ | 41 lbs. | 281 lbs. |
30XH | 30 Gallon Extra-High Rect. Tank | 24″ x 12″ x 24″ | 40 lbs. | 280 lbs. |
30B | 30 Gallon Breeder Rect. Tank | 30″ x 18″ x 12″ | 34 lbs. | 274 lbs. |
37 | 37 Gallon Rectangular Tank | 30″ x 12″ x 22″ | 44 lbs. | 340 lbs. |
40 | 40 Gallon Rectangular Tank | 48″ x 13″ x 16″ | 53 lbs. | 373 lbs. |
40B | 40 Gallon Breeder Rect. Tank | 36″ x 18″ x 16″ | 52 lbs. | 320 lbs. |
40H | 40 Gallon High Rectangular Tank | 36″ x 13″ x 20″ | 50 lbs. | 370 lbs. |
55 | 55 Gallon Rectangular Tank | 48″ x 13″ x 20″ | 62 lbs. | 490 lbs. |
55 | 55 Gallon Rectangular Tank | 48″ x 13″ x 20″ | 62 lbs. | 490 lbs. |
60 | 60 Gallon Rectangular Tank | 48″ x 13″ x 24″ | 65 lbs. | 545 lbs. |
65 | 65 Gallon Rectangular Tank | 36″ x 18″ x 24″ | 87 lbs. | 607 lbs. |
65 | 65 Gallon Rectangular Tank | 36″ x 18″ x 24″ | 87 lbs. | 607 lbs. |
75 | 75 Gallon Rectangular Tank | 48″ x 18″ x 21″ | 97 lbs. | 697 lbs. |
90 | 90 Gallon Rectangular Tank | 48″ x 18″ x24″ | 128 lbs. | 848 lbs. |
90 | 90 Gallon Rectangular Tank | 48″ x 18″ x 24″ | 128 lbs. | 848 lbs. |
110 | 110 Gallon Rectangular Tank | 48″ x 18″ x 30″ | 182 lbs. | 1062 lbs. |
110 | 110 Gallon Rectangular Tank | 48″ x 18″ x 30″ | 182 lbs. | 1062 lbs. |
120 | 120 Gallon Rectangular Tank | 48″ x 24″ x 24″ | 144 lbs. | 1104 lbs. |
120 | 120 Gallon Rectangular Tank | 48″ x 24″ x 24″ | 144 lbs. | 1104 lbs. |
120XH | 120 Gallon Extra-High Rect. Tank | 60″ x 18″ x 26″ | 157 lbs. | 1157 lbs. |
120XH | 120 Gallon Extra-High Rect. Tank | 60″ x 18″ x 26″ | 157 lbs. | 1157 lbs. |
125 | 125 Gallon Rectangular Tank | 72″ x 18″ x 22″ | 160 lbs. | 1160 lbs. |
125 | 125 Gallon Rectangular Tank | 72″ x 18″ x 22″ | 160 lbs. | 1160 lbs. |
150 | 150 Gallon Rectangular Tank | 72″ x 18″ x 27″ | 238 lbs. | 1438 lbs. |
150 | 150 Gallon Rectangular Tank | 72″ x 18″ x 27″ | 238 lbs. | 1438 lbs. |
150XH | 150 Gallon Extra-High Rect. Tank | 48″ x 24″ x 30″ | 219 lbs. | 1419 lbs. |
150XH | 150 Gallon Extra-High Rect. Tank | 48″ x 24″ x 30″ | 219 lbs. | 1419 lbs. |
180 | 180 Gallon Rectangular Tank | 72″ x 24″ x 24″ | 348 lbs. | 1788 lbs. |
220XH | 220 Gallon Extra-High Rect. Tank | 72″ x 24″ x 30″ | 392 lbs. | 2152 lbs. |
220XH | 220 Gallon Extra-High Rect. Tank | 72″ x 24″ x 30″ | 392 lbs. | 2152 lbs. |
265 | 265 Gallon Rectangular Tank | 84″ x 24″ x 30″ | 400 lbs. | 2520 lbs. |
Factors you should consider before choosing Dimensions of your fish tank
It takes more than just locating a fish tank and filling it with tap water to properly care for a fish. There are numerous aquarium options available, so you should put some thought into selecting the best one for your aquatic creatures.
Fish tanks come in a variety of forms and sizes, with some having more bells and whistles than others. That doesn’t mean you have to spend a lot of money on a fish tank, but you should think about what style of tank is ideal for you and your fish.
Understand what fish are you going to keep in your aquarium
This is an important factor because you will have to understand different characteristics of the fish like its typical behaviors, diet, pH, tank mates it is compatible with, temperature, and other parameters.
Also, you will have to understand how long the fish might grow over time and decide the tank size accordingly. You will also have to take care of the things you might have planned to do in the future; like if you ever plan to add more fish in the near future or so.
Get Necessary Equipments for tank
Along with the fish tank, you’ll need to consider the other goods required to maintain a healthy aquarium environment.
These include air pumps, gravel, a heater, a thermostat, and chemical additives to eliminate chlorine from the tank’s water. Cutting corners on equipment may have an effect on the health of your fish.
Good lighting for your fish—and you
Check that the lighting in your fish tank is balanced. Excessive illumination may cause the water to become excessively warm, resulting in algae growth. You may have difficulty spotting your pet fish if there is insufficient illumination.
Lighting is also affected by the size of your tank. A larger tank will almost certainly require more illumination than a smaller one. A decent rule of thumb is to have one to two watts of illumination per gallon of water available.
A good Filtration system
Filtration systems are used to remove debris and particles that accumulate in fish tanks. Some employ a mechanical mechanism that filters water in the tank via a spongy substance packed with charcoal.
This type of system works best in small tanks, so you might want to look into other filtering alternatives if you have a bigger one.
Does it match the place?
Your fish tank does not have to be only a safe haven for your fish. It can also serve as a beautiful item of house décor. Consider how to make a tank appear beautiful as well as the upkeep that will be required.
Fill the tank’s bottom with sand, tiny pebbles, or glass stones. Sand may give your tank a more tropical appearance, but it is more difficult to keep clean. Gravel is easy to clean and works nicely in freshwater tanks.
You may select from a variety of decorations, including plants, at this point. Fish want to have a place to hide, so keep that in mind when determining which accessories to put in your fish tank.
Size of the fish tank
The size. Consider where you’ll put your fish tank and how many fish it will contain. Some tanks are as little as one gallon, while others may hold up to 200 gallons. Choosing the proper size fish tank from the start is critical. Moving your fish might cause them further discomfort.
Positioning of Fish tank
The positioning. Make certain that your fish tank is not in direct sunlight. Avoid putting it too close to heat or air sources. These elements can raise the temperature of the water and encourage algal development.
Fish Temperament
Your fish’s temperament Learn about the fish you want to put in your tank. Different personalities may clash. Some fish are aggressive and may injure or even kill other, more passive fish.
Fish with semi-aggressive and aggressive attitudes can coexist in the same tank if the tank is large enough for them to avoid colliding. Mellow fish that get along nicely with others include neon tetras, guppies, and mollies.
How much time you have each day to devote to the upkeep of your fish.
Fish make for relatively low-maintenance pets, but they still need time and attention from their owners. Check on the status of all of the fish that are kept in your aquarium first thing every day.
Use a net to quickly remove any dead fish from the tank. In addition to this, you will need to check the water temperature on a regular basis, make sure the filters are operating correctly, and clean the tank.
I hope now you were able to understand what is the right size for your fish among these Different dimensions of fish tank.