20 Gallon Fish Tank Suggestions For Bettas

If you’re interested in getting some tank mates for your betta then a 20 gallon fish tank is a great size. At this size, you’ll be able to house fish such as tetras that need extra room to swim, as well as fish that can grow a little bit bigger than bettas, such as mollies. Whatever your choice, a 20 gallon tank is going to open up so many possibilities for different tank mates. So keep reading to find out about 20 gallon fish tanks that are going to be the best for your betta!

20 Gallon Fish Tank Suggestions

If you’re not sure where to start looking for fish tanks, then Amazon is usually a great place. In most cases, you won’t just get a fish tank, but you’ll also get some of the other necessary equipment such as filters, water conditioner, and lights. However, if your fish tank doesn’t come with that it doesn’t necessarily mean you’re missing out. A lot of the equipment that comes with a tank can be very hit or miss. Here are some of the best all-around fish tanks and fish tank kits!

Marina LED 20 Gallon Aquarium Kit

If you’re looking for an aquarium that balances quality with price then the Marina LED 20 Gal Aquarium is definitely going to be a great choice. It’s inexpensive for what you get however it definitely doesn’t sacrifice quality!

With this kit, you’re not just going to get the aquarium itself. You’re also going to get LED lights, a water conditioner, a fish net, a filter, a biological supplement, and a care guide. All this equipment is going to get your aquarium running nicely! Although it’s important to note that you are going to need to buy a heater and substrate separately.

One of the best things about this kit is the filter. It’s whisper quiet and you’ll barely hear it when it’s on. Because there’s nothing more annoying than an overly loud filter. Especially when you’re fish tank is in your bedroom or any room you wish to relax in.

As well as the filter, the lights are also amazing. When you let them nourish your plants, you’ll notice them come to life and flourish. These two bits of kit make the aquarium well worth the money and if you’re a beginner they’re a great place to start.

There are better filters and lights on the market, but in the beginning, these are going to be more than sufficient to get the job done for you!

The biggest problem I noticed with this tank is that the filter guard can be a little rough. If your betta rubs up against it then he may tear his fins. However, in most cases, your betta will probably stay away from the filter guard and if not you can always try covering it with some plants to lessen the likelihood of your betta rubbing against it.

Marina Aquarium Kit – 20 gallon Fish Tank – LED
  • 20 U.S. gallon glass aquarium
  • Includes a Marina Slim S20 clip on filter with quick change filter cartridges
  • Includes everything you need to get your aquatic home started
  • Measures: 24 inches L x 12.5 inches W x 16.5 inches H

Another issue is that you are going to have to buy a few more bits and pieces. The price isn’t going to be extortionate but it may be an extra $20-30 on top!


  • The filter is extremely quiet, you’re not going to be distracted by any loud whirring.
  • If you have live plants in your tank then the LED lights are going to be amazing for helping them grow.
  • This is the perfect tank for anyone looking to get started and also for veteran betta keepers who need another tank to house their fish.


  • The guard around the filter is rough, sometimes your betta can rub against it and injure his fins or scales.
  • You’ll need to buy a heater as well as the substrate for your tank

Seaclear Acrylic Combo Set

If you have a little bit of extra money to spend then this is the tank for you. While the Marina balances quality with affordability, this tank is going to cost a little bit more, but also has a lot more great qualities.

One of the biggest benefits of this aquarium is the fact that it’s acrylic. Acrylic tanks are 17 times stronger than standard glass aquariums as well as being lighter. While you may not think you need an aquarium that’s durable you’ll be surprised at how many people smash their aquariums by accident.

Don’t worry about what will happen when the acrylic fills with water either. It’s extremely sturdy and will hold all the water with ease, just like a glass aquarium.

On top of this, you’ll also notice the temperature in the tank fluctuating less. This is because acrylic isn’t affected by external temperature nearly as much as glass is.

You’ll also notice that looking into the tank is a lot more clear. When the crystal transparency is combined with no corner seams you can watch your betta from any angle. One customer even said, “It’s like going from normal to HD!”

SeaClear 20 gal Acrylic Aquarium Combo Set, 24 by 13 by 16″, Clear
  • Combo includes aquarium, reflector and electrical 15″ light fixture
  • Acrylic aquariums are clearer than glass, 17 times stronger, and only half the weight!


  • The main reason you should buy this tank is the fact that it’s acrylic. An acrylic tank is going to reduce temperature changes, be more sturdy than glass and give you a more clear view of your fish.
  • It also comes with an LED light fixture so you don’t have to worry about buying any!


  • The biggest problem with this tank is that you’re also going to need to buy a couple more things. Such as a heater and filter. However, for the type of tank, you’re getting it’s well worth the extra expense.
  • As well as this the top is only partly covered. So cleaning it can be more of a nuisance than a regular tank.

Aqueon Aquarium Starter Kit

Another great choice is the Aqueon Aquarium Starter Kit. It’s another kit where you’re not just going to get the tank, but other necessities as well! In fact, if you’re looking for a tank which comes with everything then this one is for you!

With this tank, you’re also going to get a heater, filter, food, water conditioner, and LED hood. This is an aquarium that you can set up and go right out of the box. Which definitely makes it beginner friendly or a great starter kit for anybody!

One of the things I love about this starter kit is the filter that comes with it. Not only is the filter quiet, but it also has a light that flashes red on it when the filter cartridge needs changing. While this is a small touch it’s so helpful for those who are forgetful. The filter is also great for fish that aren’t strong swimmers (such as bettas) but still excels at getting the job done!

The LED lights are also amazing for the price you’ve paid for them. If you want a light that is nice and bright then these lights have got you covered. They’re going to be perfect if you’re looking to add live plants to your tank, or if you just want to see your betta clearly!

Aqueon Aquarium Fish Tank Starter Kit with LED Lighting 20 Gallon High Fish Tank
  • All the equipment needed to get started in one box
  • Kit includes: glass aquarium, low profile LED hood, QuietFlow power filter, filter cartridge, submersible preset heater, premium fish food sample, water conditioner sample, fish net, thermometer and setup guide

However, one of the biggest downsides is that the heater could be better, so you’re going to be better off spending a little more money on a new heater.


  • The filter is extremely effective but isn’t going to have a negative effect on strong swimmers.
  • The filter will flash red when the filter cartridge needs changing.
  • It’s also extremely quiet, so it’s not going to be off-putting.
  • LED lights are nice and bright and would be great for growing live plants.
  • It’s a complete aquarium kit that comes with everything you need to get started.


  • While this tank does come with a heater if you have the extra money, it’s worth the investment to buy a new one.
  • Condensation can often build up on the hood.

ECOLIFE Aquaponic Garden System Tank

This is one of the coolest 20 gallon tanks you can get. In fact, not only is this a tank, but it’s also an aquaponic system. If you’re curious about aquaponics and you want to see the relationship between animals and plants then this tank is for you. However, if you just wanted a regular fish tank then you should go for one of the other three on this list.

The main benefit of this tank is that the plants will help keep your tank clean, and the bioload from your fish will help give the plants nutrients. And not only do you get the tank but you’re also going to get training on how to use it as well as customer support.

This excellent learning tool also comes with LED lights which have a lot of different programmes you can run.

Obviously, the downside to this tank is that it’s only good for people who are interested in aquaponics. It is a great bridge between the two hobbies, but not for somebody who is only interested in keeping bettas.


  • The concept is amazing and not only are going to be able to keep bettas, but you’re also going to grow your own food.
  • The LED lights are amazing and have lots of different programmes you can run.
  • A great learning tool for anybody who wants to understand the relationship between plants and animals.
  • You won’t have to clean your tank as often because the plants will be doing it for you.


  • If you’re not interested in aquaponics then this tank has a lot of useless features.
  • Because there are more moving pieces it can be more difficult to maintain then a normal aquarium.

20 Gallon Tank Mates

If you’re using a 20-gallon tank then you’ll be able to add a lot more fish with your betta. While you’ll no longer have to worry about fish that need more room to swim or who are larger, you’ll still need to take into consideration whether a fish will get along with your betta. Some great fish to choose from are:


Tetras are peaceful fish and because they aren’t brightly colored and don’t have long flowing tails your betta shouldn’t see them as a threat. You should avoid putting tetras in a tank smaller than 20 gallons. While they’re small fish they like to roam, and the extra length of your tank will allow them to do this.

As well as this you should always have tetras in a school, which can range from a minimum of 6 to a maximum of 12. 20 gallons will be more than enough for this.

If you want to read more about whether tetras and bettas can live together, and which tetras to buy then check out this article.


Another fish that shouldn’t be put in a tank smaller than 20 gallons are mollies. Mollies can grow up to 3 inches so you need a bigger tank for them to swim comfortably in. They are a great choice because of their peaceful temperament and because they’re not brightly colored and don’t have long fins.

Mollies are great choices and you’ll have a lot of fun looking after them! You can read more about mollies and bettas here.

Other Great Choices

Mollies and tetras will survive a lot better in 20-gallon tanks over something smaller. However, you can also add any of these tank mates. While 20 gallons isn’t necessary for them they’re still going to enjoy it!


Platies are live bearing fish and also great beginner fish. You can put them in your tank and not have to worry about them as they normally take care of themselves. Just make sure the water quality is great and they’re getting fed enough and watch them thrive in your tank! (Read more about platies and bettas.)

Female Guppies

Believe it or not, oftentimes you can keep guppies with bettas. But only if they’re female. Female guppies are still pretty, but they’re colors are duller and they don’t have the long flowing tail male guppies have. However, it’s always safe to take certain precautions when putting guppies and bettas together.

These are just a few of the tank mates you can add to your tank. But don’t be deterred. There are so many fish that can coexist with your betta and if you do the research you’ll find the right ones for you!

If you’re looking for a complete guide on Betta fish care, click here

How Much Gravel Will A 20 Gallon Tank Need?

When choosing a substrate I always prefer using gravel over sand for a number of reasons. If you’re wondering how much gravel you should use a good rule of thumb is 1lb for every gallon in your tank. Obviously, this will change if your tank isn’t the standard rectangular shape. And remember you only want to use high-quality gravel which isn’t too small or too large.

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