10 Gallon vs 20 Gallon Fish Tank: Which One Is The Best For You?

Fish keeping can be an amazing experience once you figure out what is the correct tank size for you. The right fish tank will not only increase the beauty of your room but also make it easier to care for your fish and other livestock.

Since the fish tanks are available in various sizes, it can sometimes confuse anyone about which one to buy. Besides, the kind of fish you want to get will also change with the tank size as well. 

On popular demand, we are going to talk about all the pros and cons and make a clear comparison of the 10 gallon and 20 gallon fish tanks so that you can decide which one is the best for you.

So, without making any delay let’s make everything clearer and start the article with this comparison table-

Comparison Of 10 Gallon And 20 Gallon Tank At A Glance

Tank Characteristics10 Gallon 20 Gallon
Size SmallerBigger 
Dimension 20” x 10” x 12”  approx 24″ x 12″ x 16″ approx
Weight when empty 11 lbs25 lbs 
Weight with water 110 lbs225 lbs
Fish Number 8-1019-20
Maintenance Easy Difficult
Price comparisonCheaper Expensive 
Fish type  Small fish or invertebratesLarge varieties of fish and other livestock

3 Things To Consider Before Getting A Tank

Tank buying guide

1. Space

At first, you have to consider the space available and according to that, you have to decide which one is the better pick for you.

When you have limited space then having a 10 gallon fish tank could be the best option for you. If the tank is bigger than the room in proportion, then cramming a 20 gallon tank in a small room might make it look odd.

Besides, make sure to choose the space you are about to put the tank in that’s safe and free from clutter.

For limited space, you can consider a 10 gallon Aqueon fish tank to be one of the best matches for your interior.

  • The tank material is made of glass and is rectangular in shape.
  • It comes with an aquarium Starter Kit and a setup guide to help you get started with the tank right away.
  • It also includes white LED Lighting and a preset heater and a thermometer as well to keep the water temperature at a constant of 78 degrees which is appropriate for your tropical fish.
  • It includes a power filter that has LED lights that indicate when the filter cartridge needs a change.
  • The complete starter kit contains samples of premium fish food and samples of water conditioner and a fish catching net as well.

And if you can allot a big space for your tank you can try Tetra Aquatic Turtle Deluxe Kit which is a 20 gallon tank.

  • It’s a complete aquarium kit that includes all the essentials needed such as filter with cartridges, basking platforms, heating lamp, boxwood plant mat, and a screen top.
  • The  ReptoFilter instantly creates a beautiful waterfall scenery  and keeps the water clean with three stage filtration.
  • The heating lamps are fixed into the screen top for prime basking and comfortable warmth for the fish.
  • It also includes samples of Tetra food and water care products too.

2. Cost

Obviously a 20 gallon tank will cost you more than a 10 gallon tank would. However, the cost will also vary depending on the material used for the tank and also on the brand of the tank as well. Before getting a tank it’s really important to decide what amount you are willing to spend on the tank itself. 

If you are willing to go a bit high on the budget you can get the luxury experience of fish keeping from  SeaClear 20 gal Acrylic Aquarium Combo Set

  • It’s made of lightweight glass
  • The Combo includes an aquarium, reflector, and an electrical 15″ light.
  • This Acrylic aquarium is clearer than glass, 17 times stronger, and only half the weight of the usual ones.
  • The great thing about this one is, it’s more resistant to impacts and less prone to cracking than normal glass aquariums.
  • It’s a much safer option if you have children or pets in your home.
  • Lastly, It’s suitable for both saltwater and freshwater.

3. Maintenance

With the glory of keeping an aquarium comes some regular maintenance work otherwise the whole system will fall apart. Normally a 10 gallon tank needs less effort than a 20 gallon tank. 

Moreover, the smaller sized filters are easier to clean as well.

But the small fish aquariums need frequent water changes and water testing as well to keep the tank waste free.

However, normally the larger fish tanks have a more stable system due to their size. So it tends to provide a more stable condition for the fish. You see, the high volume of water lets the temperature and other parameters of it change very slowly. 

As a result, the fish species have a better chance of surviving. Anyways, when it comes to cleaning, a 20 gallon tank can be a little fussy job. Though the advantage is, in a larger aquarium you can place more decorative objects and even more fish also.

What Kinds Of Fish Will Suit My Aquarium

Aquarium fish types

Before choosing what fish species to buy you have to consider the capacity of your fish tank. Normally, a 20 gallon tank can accommodate more fish than the 10 gallon one. 

Trying to get a large number of fish in a smaller tank is not a good idea. Because the small tank will not let the normal movement of the fish happen and the tank will get dirty very soon. And this will kill the fish eventually. 

So the main purpose is to keep the tank as healthy and as clean as possible with the perfect number of fish. 

Now, let’s check out what’s the ideal choice for both of the tanks–

For 10 Gallon Tanks

In a 10 gallon fish tank maximum 10 fish is ideal. But if the species grows larger, then limit the fish number to 7-8. 

For a 10 gallon fish tank, you can choose from many species of fish including betta fish, neon tetras, zebra danios, guppies, mollies, dwarf gourami, goldfish, and so on. 

Along with the fishes, you can decorate your fish tank with many decorative materials and some aquatic plants like water weeds, duckweeds, coontail, anubias etc.

Since 10 gallon tanks can get dirty more quickly than you have to change the filter cartridge or filter pads regularly. Make sure to clean and replace the filter cartridge every 4 weeks. However, if the ammonia and nitrate levels are high, change more often. 

For 20 Gallon Tanks

For a 20 gallon fish tank there are more choices of fish species available. You can put around 19-2o fishes in the tank of the species including Betta fish, Guppy, Dwarf gourami, Neon tetra, Endler’s Livebearer, Harlequin Rasbora, Corydoras Catfish, Ghost shrimp, Platy, Bristlenose Pleco etc.

Besides, you can add some aquatic plants such as java moss, anubias, amazon sword, dwarf hairgrass, water wisteria, water sprite, hornwort, pennywort, pygmy chain sword, etc. 

Frequently Asked Questions (FAQs)

Can I Use A 10-Gallon Filter In A 20-Gallon Tank?

No, it’s not a good idea to do that. Because a filter designed to work in a 10 gallon tank will not be able to clean the water properly if it’s used in a 20 gallon tank. As a result, the whole tank condition and fish health will deteriorate. So, it’s best to use the rated filter according to the tank size.

Is A 10 Gallon Fish Tank Too Small?

Normally when we compare the 10 gallon fish tank does seem like a smaller one but it’s still very suitable for having a few small fish in the homes. Just keep in mind that it will need more frequent water changes and more attention so that ammonia and nitrate levels don’t spike up.

What Happens If The Fish Tank Is Too Small?

If the fish tank is too small, the fish won’t be able to move freely and this will stress them out. Besides, in small tanks waste products like ammonia can accumulate and deteriorate the water quality. And this is harmful to the fish’s health and lifespan.


Comparing both 10 gallon and 20 gallon fish tanks is just about showing the pros and cons of each. In real terms, none of them is better than the other. Because at the end, it will all depend on what type and number of fish you choose and how you care and maintain the tank. 

For a beginner 20 gallon tank can be best as it provides a more stable condition. But when you are low on budget, a 10 gallon fish tank would do just fine. 

The main issue is as long as you keep changing the water and keep the tank clean on a regular basis, you can have any size of fish tank for yourself.

For more information about how to clean and maintain the fish tank like a pro, follow us for our next article. Hit the comment section for any further queries and don’t forget to share with your friends. 

Howard Parker

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