10 gallon tank vs 20 gallon tank

10 gallon tank vs 20 gallon tank

Both the 10 gallon tank and 20 gallon tank are popular among beginner fish enthusiasts. However, which one is better for you?
In this blog post, we will compare the two options, highlighting their benefits and drawbacks in different circumstances. By the end of this post, you should have a clear idea of which size fish tank is right for you.

Compare 10 Gallon vs. 20 Gallon Fish Tank


The first obvious difference between the 10-gallon tank and 20-gallon tank is size.

  • There are two standard measurements for a 20-gallon tank. One measurement is 24 inches long, 12 inches wide, and 16 inches tall. Another one is 30 inches long, 12 inches wide, and 20 inches tall.
  • There is one standard measurement for a 10-gallon tank, which is 20 inches long, 10 inches wide, and 12 inches tall.

Indeed, the 10-gallon tank will be more lightweight than the larger one with such measurements. However, it depends on the tank wall thickness and different brands that the weight can vary.

  • When empty, an acrylic 10-gallon tank weighs around 10lbs, and a glass one measures around 13-15 lbs.
  • When empty, an acrylic 20-gallon tank weighs around 20 lb, and a glass tank can be as heavy as 30 lbs and more.

A 2-gallon tank can hold more water and thus more fish. If you are looking to add a lot of fish to your home, then the 20-gallon tank is the better option.

Also, you should consider the available space in your house to see if it can fit which tank better. You do not want to cram a 20-inch aquarium inside a small living space.

Water quality

One of the most important factors to consider when choosing a fish tank is water quality. The 10-gallon tank and 20-gallon tank can provide good water quality for your fish if they are properly maintained.

It is required to change 1/4 of the water in the tank every month. Therefore, it is generally easier to maintain water quality in a smaller tank like the 10-gallon tank.

The ideal temperature range for most types of fish is around 76°F – 80°F. Hence, it is advisable to insulate the tank wall or place the tank near your house’s heater. Indeed, the smaller tank will be easier to warm up than a larger tank. However, if you get cold water fish, choosing either tank is fine.

Fishes need a constant supply of oxygen, so it is necessary to have oxygen filtrates in your tank. However, with warmer water, the filtration process will be slower, so a bigger tank will solve this problem since it warms up at a slower rate.

Cost and ease of cleaning

Another factor to consider when choosing a fish tank is cost. The 10-gallon tank is generally less expensive than the 20-gallon tank. This is because it is smaller and requires less equipment, including decorating accessories and filtration systems.

Additionally, a smaller tank is easier to clean and can be less expensive to set up. Therefore, the 10-gallon tank is always the better option for beginners with a limited budget and few experiences.

When choosing a fish tank, one more factor to consider is the ease of cleaning. If you are looking for an easy-to-clean tank, the 10-gallon tank is probably better. However, if you want to add a lot of fish to your home, the 20-gallon tank should suffice.

What Fish Should You Keep in a 10 Gallon Tank?

can 10-gallon filter in 20-gallon tank

Here are our top 10 picks for the best fish species for 10-gallon tanks:

  • Betta Fish
  • Guppies
  • Tetras
  • Neon Tetras
  • Danios
  • Goldfish
  • Angelfish
  • Clownfish
  • Dwarf Gouramis
  • Cherry Shrimp

What Fish Should You Keep in a 20 Gallon Tank?

Here are our top 10 picks for the best fish species for 20-gallon tanks:

  • Betta Fish
  • Guppy
  • Dwarf Gourami
  • Neon Tetra
  • Endler’s Livebearer
  • Harlequin Rasbora
  • Platy
  • Corydoras Catfish
  • Bristlenose Pleco
  • Ghost shrimp

Can I use a 10-gallon filter in a 20-gallon tank?

No, you should not do that. The filter will not be able to filter the water and clean the tank properly. Additionally, the 10-gallon filter will not be able to move the correct amount of water through the tank to keep the fish healthy.

It’s always best to err on the side of caution and go with a rated filter for your tank size.


When choosing a fish tank, it’s important to consider the size of the tank, the type of fish you want to keep, and your budget. Between the 10-gallon tank and the 20-gallon tank, each type works better for different living spaces, expenses, and maintenance effort. However, a beginner should start with the smaller tank since there will be fewer problems and less cost to worry about.

Which one should you buy? Well, the answer depends on your needs.

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