How Many Cichlids in a 20 Gallon Tank?

Estimated read time 11 min read

Are you thinking of getting cichlids to add a splash of color to your aquarium? And wondering how many will fit in a 20-gallon tank?

Though it is advised that you keep your cichlids in a large tank of at least 55 gallons, there are some small cichlid variants that you could put in a 20-gallon tank in a group of 3 or less.

Let’s delve into more details on the cichlid varieties that could be put in a 20-gallon tank, know about the ideal tank size for cichlids, and also have a look at the cons of putting bigger cichlids in a 20-gallon tank.


What Is the Best Tank Size for Cichlids?

​​While deciding on the best tank size for cichlids, factors such as species, size, and temperament should be considered. For example, African cichlids are generally a very active and aggressive fish variety that requires a lot of space for harmonious cohabitation.

African cichlids require a tank size of at least 55 gallons to accommodate at least 15 of them. Therefore, if you want to add more fish to the tank, you should add extra gallons of water per each fish added.

Cichlids that are six inches long are considered large and should be kept in a 30-gallon tank. On the other hand, smaller cichlids require less aquarium space than the bigger cichlids and could be contained in a 20-gallon tank.

Also, keep in mind that the fishes are bound to grow, so plan your aquarium accordingly.

How Many Cichlids per Gallon?

Size and territorial behavior are the two most important factors to consider before deciding how many cichlids could be added per gallon. It is widely recommended to have 1 gallon of water per cichlid and 5 gallons of water for the African variant of cichlids.

Here is a handy table to look at before bringing home a cichlid.

Tank sizeNumber of Cichlids
75 gallons6
60 gallons5
55 gallons4
40 gallons4
30 gallons2
20 gallons1 cichlid or up to 2-3 small cichlids


How Many Gallons Does a Cichlid Need?

Again, it all boils down to the species and size of the cichlids you intend to raise.

A 20-gallon tank would be enough for young cichlids, but a group of cichlids cannot sustain it as they grow and develop fully.

Cichlids, by nature, are aggressive, and their territorial behavior might raise concerns as they grow up. So it is always better to house them in large tanks. In short, give the cichlids more space than what their size asks for.

Even the smaller types of cichlids grow more than 4 inches in size. So even if we go by the rule of at least 1 gallon per inch, most cichlids would require a minimum of 4 gallons per fish initially.

And when you consider the African cichlid variety, their size varies from 2 to 12 inches long when fully developed and thus requires a lot of aquarium size to house them. So, in short, the bigger the tank, the better to accommodate the cichlids.

Which Cichlids Can You Keep in a 20-Gallon Tank?

Some cichlids varieties could happily fit into a 20-gallon tank as long as they are well maintained. The tank should have all the necessary add-ons that would help the cichlids’ well-being.

And it is not advised to have more than a pair of cichlids in a tank with a capacity of 20 gallons. Below listed are the types of cichlids that could be easily kept in a 20-gallon tank.

Ram Cichlids

Ram cichlids are a peaceful variety of freshwater fish requiring significantly less maintenance than the usual aggressive behavior displayed by cichlid varieties. They are an easygoing community member as well.

The ram cichlid variety of freshwater fish lives at a temperature of 71.6-82.4 Fahrenheit. Therefore, though not aggressive by nature, the German blue ram varieties could get provoked by other fish.

German rams can live for up to three years in a small water tank of 10 to 20 gallons. But you must ensure that the water used in the tank is freshwater and the aquarium is perfectly set with plants and rock formations.

Convict Cichlids

Convict cichlids (Amatitlania nigrofasciata), a freshwater cichlid species, are primarily seen in Central American countries. When fully grown, the average size of convict cichlids comes around 4-5 inches, and they are very small compared to the other varieties of cichlids.

Since they are small even when fully grown, they could perfectly fit into smaller tanks compared to other cichlid varieties that need a larger tank when fully developed.

Thus, convict cichlids need no special accommodations, as they exhibit a reasonably standard growth rate. The male convict cichlids tend to be larger than their female counterparts, but their gender can’t be identified until they are adults.

Kribensis Cichlid

Kribensis cichlid is an anomaly in the aggressive cichlid fish family which is notorious for its bullying habits. Instead, Kribensis cichlid (Pelvicachromis pulcher) is a peaceful species that thrives in community surroundings. They belong to the dwarf cichlid family.

Though they don’t need a large tank, the larger the tank size, the more their happiness would be. So though some aquarists even use 10-gallon tanks, it’s not advisable.

Agassizi’s Dwarf Cichlid: Apistogramma agassizii

Agassizi’s dwarf cichlid (Apistogramma agassizii) is another sought-after cichlid variety because of its beautiful coloration and peaceful nature. In addition, Agassizi’s dwarf cichlid is a freshwater cichlid fish variety that doesn’t require much maintenance.

They would thrive in an adequately maintained aquarium with plenty of rock formations, plants, and a sandy substrate. Agassizi’s dwarf cichlid is also compatible with other fish species because of their peaceful demeanor.

Cockatoo Cichlid: Apistogramma Cacatuoides

Cockatoo cichlids are another cichlid variety that is ideal for a 20-gallon tank. They have a body type that is typical of dwarf cichlid species. In addition, the size of female cockatoo cichlids is comparatively smaller (2 inches) than male cockatoo cichlids (4 inches).

The cockatoo cichlid variety has a life span of about five years and is known for its peaceful nature and lack of aggression. In addition, cockatoo cichlids adapt well to their environment, making them ideal for community tanks.

Because of their tiny size, they could be housed in a 20-gallon aquarium even when they are fully developed. They could also be housed with other small species of fish.

Umbrella Cichlid

Umbrella cichlids are known to thrive in groups, and an isolated aquarium space would make them feel alone. Though you can raise a pair of umbrella cichlids in a 20-gallon tank, a larger tank is recommended for groups.

Umbrella cichlids would rather flee from the sight than confront a bully fish. The male umbrella cichlids do show aggression within a group, but generally, they tend to hide in the presence of a larger and slightly aggressive fish.

Dwarf Cichlid

A dwarf cichlid, as the name suggests, is small in size when compared to the larger and more aggressive variants of the cichlid family. Dwarf cichlids can be very well housed in an aquarium with a size of 20 gallons.

Though you can put 5-6 dwarf cichlids in a 20-gallon tank, it is always advised to go for large tanks to ensure peaceful and healthy co-existence. Dwarf cichlids are easier to maintain when compared to their aggressive counterparts.

Adding a school of fish to a 20-gallon tank can be an exciting and rewarding experience. Find the perfect species that will thrive in a smaller environment while still displaying the captivating behaviors of schooling fish. Read our comprehensive guide on the best schooling fish for 20-gallon tank and create a lively, dynamic centerpiece for your home or office today.

Why Can’t You Keep Bigger Cichlids in a 20-Gallon Tank?

Bigger species of cichlids thrive in groups, making it impractical to hold them in confined and limited spaces. In addition, they would love to swim around, and a small tank could act as a hindrance and limit their movement.

The most popular and most extensive cichlid variety is the African cichlid species. They could grow up to 12 inches, making it impossible to breed them in a 20-gallon tank. Fully-grown African cichlids require a tank of 55 gallons, and only the young African cichlids that are two or three inches long can be housed in a 20-gallon tank.

African cichlids of average size would require a 30-gallon tank and five gallons of water per additional fish. However, if you are keen on keeping the young African cichlids in a 20-gallon tank, they will grow to double to triple their original size.

Also, why make the life of these poor fishes difficult by piling up them in a small tank? You can always go for the small varieties of cichlids if you have a smaller tank. However, if you intend to get the bigger cichlid variants, it is a necessity to get a bigger tank if you have their happiness and well-being in mind.

What Happens If You Keep Bigger Cichlids in a 20-Gallon Tank?

If you are still thinking that it’s not a big deal to house a couple of bigger cichlids in a 20-gallon tank, you must know about the repercussions of this action. Stocking bigger cichlids in a 20-gallon tank is nothing but a recipe for disaster.

For example, African cichlids would exhibit aggressive territorial behaviors in an overcrowded tank, such as chasing and nipping other fishes in the tank. Bigger cichlids such as the African cichlid variety are very active and need a lot of hiding places and cavities to claim as their own.

And if you put bigger cichlids in a 20-gallon tank, it will harm your tank and the fish. The fish may even hurt each other to death! Now that is the last thing an aquarist would want to happen, right?

You can always use your spare 20-gallon or 10-gallon tanks as a temporary home for young cichlids of the bigger cichlid family or as an occasional isolation home for sick fish situations. Below are some of the scenarios that could occur if you use a 20-gallon tank to house bigger cichlids.


The natural environment of bigger cichlids is a large space filled with plants, rock formations, cavities, and lots of hiding places. Though overcrowding is a strategy used to reduce the aggression of African cichlids, overstocking them in a small tank is only going to backfire.

The overcrowding strategy to tame aggression will only work if you use a large tank and extra filtration.

High Waste Production

Cichlids are known to generate more waste than an average freshwater fish. So if you don’t have a robust filtration technique to clean your tank regularly, your fish will be harmed by the toxic waste.

An overcrowded 20-gallon tank with cichlids would produce more waste than the tank could handle and ultimately lead to the fish’s poisoning.


Cichlids, especially the bigger varieties like African cichlids, are notorious for their aggression and bullying habits. So adding a group of cichlids to a 20-gallon tank will lead to the fishes fighting amongst each other.

Bigger cichlid varieties aren’t peaceful but territorial by nature, and they are bound to bully other fish into making them stay away from their space.


Cichlids can get stressed around other fish as they fight with each other for territory. So they would resort to aggressive tactics and bullying to become the dominant ones among the lot.

The egoistic cichlids might hurt each other in the process. For example, if a weak cichlid is part of the group, it would be attacked first by the dominant ones.


Like every overcrowded situation, a group of crowded cichlids kept in a 20-gallon tank will ultimately suffocate.

Final Thoughts

As an aquarist, it becomes your duty to ensure a safe living space for the fishes that you breed. If you are a beginner when it comes to cichlids, it would be best to go for the peaceful ones that could happily live in a 20-gallon tank.

But if you are more seasoned and wish to get a group of cichlids, do make it a point to purchase a larger tank that perfectly caters to the requirements of a large group of cichlids.

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