How many Angelfish in a 20-gallon tank?

In this post, we will discuss the topic “How many Angelfish in a 20-gallon tank” and all steps of setting up an Angelfish aquarium. 

How many Angelfish in a 20-gallon tank

A 20-gallon tank can fit up to 2 small-bodied or young Angelfish. Although, once the juvenile Angelfish grow, you will need to move them to a bigger tank, at least 29-gallon in size. Only then you will be able to attend to the whole requirements Angelfish have. They will have plenty of space to hide and establish their territory.


Angelfish are popular in the ornamental aquarium trade. They are easily found in many aquariums worldwide. They are triangular-shaped Cichlids and have wonderful colouration, making them great additions to tanks. Their temperament is semi-aggressive. These fish are mostly peaceful. However, they can get somewhat aggressive in some contexts. 

They are low maintenance and make awesome community fish. Angelfish grow up to 6 inches in length and 10 inches in height, for this reason, they require more space than suggested by the general thumb rule of “1 inch of fish length per gallon of water”. Their life expectancy is around 10 to 12 years.

Natural habitat

Angelfish are originally from the Amazon River basin, in South America. This area cover territories in many countries, including Peru, Brazil, and Colombia.

These fish occupy slow-moving warm water bodies. These areas are heavily-vegetated with a fine substrate.


Angelfish are omnivores. In the wild, they usually feed on the bottom. They dig around searching for earthworms and small crustaceans. However, they may also feed on larvae and smaller fish.

In a tank, these fish can be fed with many items, from industrialized flakes to live food and vegetables. It is important to keep a protein ad fibre-rich diet for these fish. Additionally, it is recommended to feed them twice or three times per day.


As mentioned above, Angelfish are semi-aggressive fish. In general, they will have pacific and calm behaviours. Thus, choosing tank mates is a task that requires research and caution. 

Angelfish are usually more sociable during early ages. Adult Angelfish are prone to aggressive territorial behaviours and also for breeding purposes.

Angelfish may become a bit aggressive when feeling threatened or unsafe. However, you can control this type of territorial or hostile behaviour by adding more Angelfish and no large fish species.

Some fish and non-fish potential Angelfish tank mates are listed below with their compatibility grade:

–       Platies – 10/10;

–       Corydoras catfish – 10/10;

–       Bristlenose Pleco – 10/10;

–       Dwarf Gourami – 8/10;

–       German Blue Ram Cichlids – 9/10;

–       Swordtails – 10/10;

–       Keyhole Cichlids – 10/10;

–       Kribensis Cichlids – 6/10;

–       Kuhli Loaches – 9/10;

–       Lemon Tetras – 9/10;

–       Rummy Nose Tetras – 6/10;

–       Guppies – 8/10;

–       Mollies – 10/10;

–       Head and Tail Light Tetras – 8/10;

–       Malaysian Trumpet Snails – 8/10.

Angelfish Tank requirements

Once Angelfish are native to the Amazon River basin the tank conditions must be kept similar to those found in the natural environment. 

These fish do not require a lot of attention from the owner as they can do just fine in a wide range of conditions. 

Water parameters

It is important to use high-quality water high-quality sources to fill up your fish tank. It is also possible to buy some water from fish stores. The recommendation is to buy water directly from the fish shop. This is because it is a manner to guarantee that the water is chlorine-free and follow other safety recommendations.

It is also extremely important to test all the water parameters when setting a tank up. Test the water pH only 24 hours after filling the tank up. The ideal pH level should be between 6 and 8. If the levels are not right, you can correct them using chemical buffers or using natural substances such as crushed coral and shells or wood.

Angelfish requirements for water hardness are between 3 and 8 dKH. And the temperature must be kept between 78 and 84 degrees Fahrenheit. You can opt for using a heater and thermostat to keep the temperature stable.

Tank size

As explained at the beginning of this post, Angelfish can measure 6 inches in length and 10 inches in height. For this reason, they require larger tanks. 

Although Angelfish are not schooling fish, they prefer being kept with some conspecifics. However, a 20-gallon tank can house only 2 small Angelfish. 

When fully grown, the Angelfish pair will require at least a 29-gallon tank. If you opt for keeping a small group of 5 or 6 individuals, make sure to have at least a 55-gallon tank available.

Water filtration system

It is very important to keep a high quality of the water. For this, a good filtration system is recommended. Additionally to this filtration system, it is also recommended to keep a water change routine of 10 to 25% changes once or twice a month.

The filtration system and the water change routine will avoid fungi and bacterial infestations, and thus, will assist you in keeping your Angelfish healthy. Additionally, Angelfish fish do not enjoy strong currents. Thus, you should have a slow-current filtration system.


Angelfish natural habitats are heavily-vegetated areas. Thus, when keeping Angelfish in tanks it is strongly recommended to have many live plants.

Angelfish appreciate hiding spots, thus the vegetation could offer them this protection. Additionally, they are somewhat territorial fish and the plants will help them on establishing it more easily and with no need for aggression.

In addition, live plants will help you with water quality, as they oxygenate the water and remove some substances also.


In this post, we discussed “How many angelfish in a 20-gallon tank” and all steps of setting up an Angelfish aquarium.

If you have any thoughts or doubts, feel free to drop us in a comment below!

Frequently Asked Questions (FAQs): How many angelfish in a 20 gallon

How many Angelfish can you have in a 20-gallon tank?

A 20-gallon tank is enough for only two small Angelfish. However, when the Angelfish are fully grown, you may need a larger tank of at least 29 gallons.

What fish can live with Angelfish in a 20-gallon tank?

If you have a 20-gallon or larger, there is plenty of space to set up one of the Angelfish and a few Corydoras and Tetras.

Are Angelfish solitary fish?

No, Angelfish prefer being kept within a group of equals. This group is recommended to have at least 4 Angelfish.

What size tank is required for 2 Angelfish?

A 20-gallon tank is the minimum tank size for 2 small Angelfish. Although, when these Angelfish grow, you will be required to move them to a larger tank.

How many Angelfish can you have in a 60-gallon tank?

A 60-gallon tank would be enough to house a small group of 5 or 6 Angelfish. This space would also be enough for setting some plants, substrate, and decorations.

Do Angelfish require live plants?

No, Angelfish do not require live plants. However, it is strongly recommended to keep plenty of live plants with Angelfish, as they can provide the fish with hiding spots and assist with keeping high water quality.


Angelfish Care Guide.

Angelfish Complete Care Guide, Size, Life Span, Tank Mates, Breeding. 2020.

Jason. 2017. 15 Great Angelfish Tank Mates (Complete Compatibility Guide).

Ribeiro, F. D. A. S., Vasquez, L. A., Fernandes, J. B. K., & Sakomura, N. K. (2012). Feeding level and frequency for freshwater angelfish. Revista Brasileira de Zootecnia, 41(6), 1550-1554.

Ahmed, L. S., Ahmed, S. M., Ali, H. S., Kamel, Y. Y., & El-Allawy, T. A. (1990). Cause of mortality in aquarium fish, angelfish (Pterophyllum scalare). Assiut Veterinary Medical Journal, 23(46), 179-187.