Angelfish can get pretty big and easily kept in an aquarium with fresh water. Although they can be easily kept in a tank, is it okay to keep them in a 20-gallon tank? Or do we need a larger tank?
Can Angelfish live in a 20 Gallon Tank? Angelfish can live in a 20 Gallon tank, and you can keep up to four Angelfish in the tank, but only when they are small. When it comes to adult Angelfish, you can only keep one full-grown Angelfish in a 20 Gallon tank.
In this article, you will get an overall idea about the size of an adult Angelfish and the requirements relating to the tank size. You will also get to know about the types of fish that can be suitable for 20 Gallon tanks and the specific number of fish that will be appropriate.
So, what are you waiting for? Let’s begin.
Angelfish And Its Size

The freshwater fish from the cichlid family, Angelfish, are of two types; Freshwater Angelfish and Saltwater Angelfish. They are peaceful but can attack other small fishes. They even fight with their own kind during the breeding season.
Angelfish are native to tropical South America. The Freshwater Angelfish can grow up to six inches, and their longer fins can grow up to 8 inches.
Usually, the female Angelfish are smaller than the male ones. Their bodies are more rounded, whereas the male Angelfish have a thin pointed tube-like structure. They have long fins, which makes them a lot taller and wider.
As a result, you can imagine when they get bigger, they will need more space so that a larger tank can be a must. Because with the substrates and plants added to the tank, Angelfish will need more space to move freely in a spacious environment.
How Big of A Tank Do Angelfish Need?
There is common thinking that the 6 inches tall Angelfish will not require a tank bigger than 5 or 10 Gallon, which is not true. Because a 20 Gallon tank can be suitable for only one Angelfish, each additional fish will require 10 to 15 Gallons more.
That is, you cannot keep your Angelfish in a suffocated area and make them feel they are living amidst nature. Do be cruel while providing a spacious environment for the Angelfish.
Although you can keep two Angelfish in a 30 Gallon tank, you also need to know how many Angelfish should be kept together.
You would be glad to hear that you can keep one pair of Angelfish, just to make sure they live in peace and without showing any kind of aggression.
But when they are small, you can keep 2 to 3 pairs of Angelfish so that they can choose their preferred mates, and then keep them in pairs after a definite time.
However, you can also keep more than two Angelfish together, but you need to make sure the tank size is bigger.
But if you notice any kind of aggression, I highly recommend keeping them separately as soon as possible.
How Many Fish Can I Have In A 20 Gallon Tank?
There is a common rule of thumb is that in a 1 Gallon tank, you can keep one 1-inch fish. That is, 20 Gallon tanks, you can keep twenty 1-inch fish.
But there is no definite answer to this question as fishes have different sizes and requirements. Try not to overcrowd your aquarium while adding more fish.
However, you also need to think about the substrates and the plant you will keep in that 20 Gallon tank.
You might also need to think about the tank mate and their prospective size, which will be staying the same 20 Gallon tank.
List of seven fish that can be kept in a 20 Gallon tank with the total number;
Name of The Fish | Size | Total Number of Fish |
Angelfish | 6 inches | 1 |
Tetra | 1.5 inches | 10 |
Barbs | 2.8 – 3.9 inches | 6 |
Guppies | 1.4 – 2.4 inches | 12 |
Mollies | 4.5 inches | 5 – 6 |
Platies | 2 – 3 inches | 12 |
Pygmy Corydoras | 2.5 inches | 6 – 9 |
Now that you have a complete idea about the list of fishes that can be kept in a 20 Gallon tank, let me provide you four combos that you can keep with Angelfish;
Combo 1 | Combo 2 |
1 full grown Angelfish 4 Barbs1 Male + 5 Female Mollies | 4 Tetras4 Mollies1 full grown Angelfish |
Combo 3 | Combo 4 |
4 Platies1 full grown Angelfish 4 Pygmy Corydoras | 4 Guppies1 full grown Angelfish 4 Pygmy Corydoras |
How Many Angelfish Can You Keep In A 20 Gallon Tank?
Angelfish usually can get up to 6 inches in length. However, they are wider fish and have spacious fins. Both male and female ones have got them.
This is the reason why the Angelfish require a taller or bigger tank. When you have a 20 Gallon tank, you can only put up to 4 small Angelfish.
But as they get bigger, you will need a bigger tank as just to keep 1 full-grown angelfish, you will require 20 gallons and additional 10 gallons for adding additional angelfish.
Nonetheless, you cannot keep four adult Angelfish together in a 20 Gallon tank. It might make them suffocate with other things present in the tank. I suggest you keep only one adult Angelfish in a 20 Gallon tank.
Note: It’s recommended to keep angelfish in pairs; so, if you have a 20-gallon tank, you can keep two or more young angelfish for the moment, but as they grow, you should move them to a larger tank.
Recommended Tank Size For Different Number of Angelfish:
No. of Angelfish | Minimum Tank Size |
1 | 20 Gallons |
2-4 | 40 Gallons |
3-4 | 50 Gallons |
4-5 | 55 Gallons |
5-6 | 75 Gallons |
Note: The above table, shows recommended tank size for full grown Angelfish only. If you have younger or smaller angelfish, they might do well in comparatively smaller tank. As angelfish grows really fast, its better to get a bigger tank in the first place.
Why Do Angelfish Need A Bigger Tank? – The Complete Explanation

There are a few reasons behind the reason for keeping Angelfish in a bigger tank. First, let me tell you, the tank needs to have spacious space for the substrates and planet. After adding these, you also need to think about the tank mates and their sizes.
So, the reasons for Angelfish needing a bigger tank includes;
1. The size of an adult Angelfish
Angelfish are very small when they are young, but they can get up to 6 inches taller when they are adults. It would help if you kept in finding that it is your responsibility to provide adequate space to grow up.
2. The shape and structure of the Angelfish
Angelfish are not only taller but also wider. They can get really big and require bigger space. Both male and female Angelfish have fins, the pointed and the spreader fins, respectively.
Moreover, they have rounded or tube-like bodies that can be around three to four inches wider. As usual, the bigger body will definitely need bigger space.
3. The presence of other tank mates
When identifying the ideal tank size, you also need to make sure what tank mates your Angelfish will be having. Depending on their size, the tank size might be bigger.
4. The addition of the Substrates and plants
Substrates, driftwoods, and plants will take a lot of space in the tank. So, if you have a 30-gallon tank, it doesn’t necessarily mean that the tank will have 30 gallons of water. That’s why it’s better to go with bigger tanks.
You just can’t remove the substrate, plants just to provide more space for the fishes.
You know, when the fish are kept in a tank, you need to make them homely, and without the substrates, it will never be possible.
Then again, the substrates and plants will kill most of the space, and this might cause the fish to feel suffocated. To avoid such a thing, a bigger tank is a must.
Related Questions:
Can I keep Three Angelfish in a 20 Gallon Tank?
Yes, you can keep three small-sized Angelfish together in a 20 Gallon tank but not full adult ones.
If you keep three adult angelfish, you will have to change the water more frequently, they can feel suffocated, and it might stress the angelfish.
But I would highly recommend you to keep only two adult Angelfish in the 30 Gallon tank and remove the unpaired one from the tank for the betterment of the fish.
Can You Keep Just Two Angelfish?
Yes, if the Angelfish are paired, and the tank is large enough, you can definitely keep them in together. This is why you will notice hobbyists looking for paired Angelfish to keep in the same tank.
What Size Tank Do I Need for Two Angelfish?
You can keep two young angelfish in a 15 Gallon tank. But when they get bigger or reach adulthood, you need to keep them in a 30 Gallon tank.
Can An Angelfish Go In a 15 Gallon Tank?
Keeping Angelfish in a tank smaller than 20 Gallons is not recommended. As they need to be kept at least in a pair and need more space to spread their fins, without any doubt, you will need a 20 Gallon tank.
Can I Have a Single Angelfish?
Yes, you can have a single Angelfish in a particular tank. But let me warn you, it might negatively impact the fish as it will mostly be stressful due to isolation. Experts suggest keeping at least 2 Angelfish in the same tank. Remember, they need to be paired.
Final Thoughts:
Such a beautiful Angelfish can get bigger and require a tank that is equal to 20 Gallon or more. It would be best to keep in mind that they are bigger and more spacious and carry spread fins.
As a result, they require a lot of space. You cannot forget the fact that the aquarium fish will also need substrates and plants, which will comprise much space. Then there is the presence of different tank mates.
Thus, a bigger tank is required. Avoid keeping a single Angelfish in a tank. Always keep them in pairs.