Standard Aquarium Sizes | Tank Dimensions,Length, Width, Height & Weights

Standard Aquarium Sizes | Tank Dimensions,Length, Width, Height & Weights

Aquarium Size
Aquarium Size

Aquarium Size

  • Who does not want to have a luxurious and perfect aquarium size for fish?

Truth is all the fish lovers are looking for the best size aquarium to keep the fish species of their own choice. But how to pick the best aquarium that is large enough to entertain different fish species?

Don’t worry.

In this healthy guide, we will help you out in choosing the best aquarium size for your home that can entertain your favorite fish species.

Moreover, will also discuss the different fish tank sizes and the best tank size for freshwater and saltwater fish. If you are a beginner then this guide is going to be your best companion in choosing the perfect fish tank size.

Let’s embark on the journey of choosing the best aquarium size.

Different Aquarium Sizes:

Aquariums are available in a large variety with different sizes. For a better understanding that which aquarium is best for a particular fish size, we will divide the aquarium into three major categories on the basis of its size.

The smaller the size of the fish tank or aquarium, the smaller the size of fish it can entertain. Similarly, large size fish tanks can entertain large size fishes.

Fish tank or aquarium are divided into small aquariums, medium aquarium, and a large aquarium. Let’s have a look at them one by one:

  • Small Aquariums:

Small size aquariums are for keeping small fishes. To understand the size of small aquariums we have listed below the number of water gallons, its dimensions, empty weight, and filled weight.

The dimensions of small size aquarium start from 12”*6”*8” and can hold 2 and a half water gallons. This category of an aquarium consists of 5 aquaria of different sizes. If you are finding hard to consider the fish tank dimensions while buying the fish, you can consider the number of water gallons it can hold.


Tank Size L×W×H Filled Weight Empty Weight
2 1/2 Gallon 12″ ×6″ ×8″ 27lbs 3lbs
5 Gallon 16″ ×8″ ×10″ 62lbs 7lbs
10 Gallon “Leader” 20″ ×10″ ×12″ 111lbs 11lbs
15 Gallon 24″ ×12″ ×12″ 170lbs 21lbs
15 Gallon High 20″ ×10″ ×18″ 170lbs 22lbs
  • Medium Size Aquariums:

The second category of an aquarium consists of medium size tanks that include seven different fish tanks. The length of these aquariums starts from 24 inches and goes up to 48 inches.

In other words, it can entertain the water starting from 20 gallons to 40 gallons. Therefore, if you are choosing the fishes that need water from 20 gallons to 4o gallons on average then medium aquarium sizes are the best choice.

Tank Size L×W×H Filled Weight Empty Weight
20 Gallon High 24″ ×12″ ×16″ 225lbs 25lbs
20 Gallon Long 30″ ×12″ ×12″ 225lbs 25lbs
25 Gallon 24″ ×12″ ×20″ 282lbs 32lbs
28 Gallon 30″ ×12″ ×18″ 330lbs 40lbs
30 Gallon Breeder 36″ ×18″ ×12″ 384lbs 48lbs
40 Gallon Breeder 36″ ×18″ ×16″ 458lbs 58lbs
40 Gallon Long 48″ ×12″ ×16″ 455lbs 55lbs
  • Large Aquariums:

Large fish tanks are designed to entertain large fish species that need a minimum of 50 gallons of water in the aquarium. The large aquarium sizes can hold a maximum of 225 gallons of water at a time and are best suitable for large fish species with great water requirements. Have a look at the below table for a clear vision.

Tank Size L×W×H Filled Weight Empty Weight
50 Gallon 36″ ×18″ ×19″ 600lbs 100lbs
55 Gallon 48″ ×13″ ×21″ 625lbs 78lbs
65 Gallon 36″ ×18″ ×24″ 772lbs 126lbs
75 Gallon 48″ ×18″ ×21″ 850lbs 140lbs
90 Gallon 48″ ×18″ ×24″ 1050lbs 160lbs
125 Gallon 72″ ×18″ ×21″ 1206lbs 206lbs
150 Gallon 72″ ×18″ ×28″ 1838lbs 338lbs
180 Gallon 72″ ×24″ ×25″ 1870lbs 430lbs
225 Gallon 72″ ×27.5″ ×27.5″ 2158lbs 358lbs
  • Extra Large Tank Size

Extra Large tank Sizes are specially built for those fishes that require more than 225 Gallons of tank water. The Tank Size Ranges From 240 to 500 gallons.

Tank Size Length Width Height
240 Gallons 96″ 24″ 24″
260 Gallons 72″ 24″ 36″
300 Gallons 96″ 24″ 30″
500 Gallons 96″ 24″ 48″

Best Aquarium Size According to the Type of Fish Species:

There are numerous freshwater and saltwater fish species that are popular among fish lovers. However, freshwater fishes require less maintenance and effort for keeping at home and are kept at home in a large number. On the other hand, saltwater fishes require high maintenance, therefore, they are not as trendy as a household pet.

Below we will look at the aquarium sizes required by the saltwater fishes and freshwater fishes. So, you can choose the type of fish and can pick the aquarium size accordingly.

Aquarium Size for Common Freshwater Fish Species:

Freshwater fishes are in high demand as a household pet because they are easy to look after. Moreover, they are of small size and require a small fish tank that can be placed in any room. The size of freshwater fishes is from 1.5 inches to 2 inches, thus they are easy to maintain.

Similarly, these small fishes require a small quantity of water that is a minimum of 5-gallon water. But it is recommended to go for a tank that can hold 10 gallons of water.

Still, it varies from fish species and a number of fishes in a tank. For a single freshwater fish go for an aquarium size of a minimum of 5 gallons of water.

Look at the below table to get a clear vision of aquarium size for freshwater fishes.

Freshwater Fish Fish Size Water Tank Dimensions
Betta Fish 3 inches 2.5 Gallons 12″×6″×8″
Guppies 2 inches 1 Gallons 7.50″×7.50″×10.25″
GoldFish 5 inches 10 Gallons 20″×10″×12″
Neon Tetra 1.5 inches 1 Gallons 7.50″×7.50″×10.25″
Zebra Danios 2 inches 2.5 Gallons 12″×6″×8″

Aquarium Size for Common Saltwater Fish Species:

Saltwater fishes are greater in size that is from 3 inches to 7.9 inches. Therefore, these fish species require a large tank and quantity of water. Moreover, they are not preferred as household pets because they need large aquarium sizes and demand high effort and maintenance level.

However, if you are still willing to have a saltwater fish species then the key tip is bigger the tank size better it will be for fish. For saltwater fishes, aquarium size should not be less than 20 gallons of water. The recommended aquarium size is the one that can hold 55 gallons of water.

Have a look at the below details for choosing the tank size for saltwater fishes.

Saltwater Fish Fish Size Water Tank Dimensions
Clown Fish 3 inches 30 Gallons 36″×18″×12″
Green Chromis 3.5 inches 30 Gallons 36″×18″×12″
Six Line Wrasee 3 inches 30 Gallons 36″×18″×12″
Auriga ButterflyFish 9 inches 125 Gallons 72″×18″×21″
Yellow Tang 7.9 inches 75 Gallons 48″×18″×21″

How much does a gallon of water weigh?

The weight of the water gallon depends on the type of water gallon you are using. There are two main types of water gallons. One is known as US gallon and the other is UK gallon.

One US gallon contains 3.785 L of water. One liter of water is equal to 2.204684 pounds. So, one US gallon contains 8.3447 pounds of water.

One UK gallon contains 4.546 L of water and one liter of water is equal to 2.204684 pounds. So, one UK gallon contains 10.0227 pounds of water.

Now after knowing the quantity of water in a gallon, you can easily choose the required aquarium size for your fish.

Related: Aquarium Calculator: Tank Volume,Heater & Chiller Size & More

Why do we consider Aquarium Size?

Aquarium size and dimensions play an important role in the nourishment of the fish. Every fish required a certain level of water in which it can live well without any hassle. Aquarium with different size and dimensions have different water capacity.

For example, the water intake capacity of some tanks is 6 gallons while some gallons support 50 gallons of water. Keeping a fish that need 30 gallons of water in a tank that can hold 6 gallons of water is not appropriate. It is an alarming situation for the fish owner as it will affect the health of fish.

In fact, if the fish tank is smaller than the required size and contains less water, then it can lead to lack of oxygen and different chemicals will build up in the tank.

Ultimately, all this leads to the death of the fish. Therefore, considering the size of the aquarium while buying the fish tank and fish is very essential.

Before keeping the aquarium and fish at your home, dig deep into the aquarium sizes and aquarium dimensions. Moreover, first, choose the fishes you want to buy and then pick the best aquarium size for them.

How do I choose the Right size Fish Tank?

If you are beginner are facing the hassle that how to choose the right size fish tank then it is no more now. Follow the below two steps and pick the best aquarium size for your fish.

  • Firstly, consider the type and number of fishes you want to keep in your home. After that, check from the above-given details that how much water the fish (you have chosen) required. Minimum water required by freshwater fish is 5 gallons whereas minimum water required by a saltwater fish is 20 gallons.
  • Secondly, choose the aquarium size that can hold the required quantity of water gallons. That is a minimum of 5 water gallons in case of freshwater fishes and a minimum of 20 water gallons in case of saltwater fishes.

After following the above two steps, you will end up having the right size aquarium for your fish.

Wrapping up:

First, dig deep into the aquarium sizes and the fish species you wanted to buy. As it will make the process of choosing the best size fish tank super easy.

Thus, the above healthy and informative guide will assist you in choosing the best aquarium size for your fish. And the hassle that what aquarium size do I need is no more now.

Flora is a Fish Parent & Enthusiast for over 10 Years. She has Deep Love & Affection for Fish Keeping. It's become her Passion to Help others. Stay Tuned with her Blog to Know more about Pet Care Tips, Product Reviews, and Guides. If you've anything Interesting to Share about your Fish. She'd Love to Know.