How Many Clown Killifish In 5 Gallon? The Complete Guide To Tank Setup And Tank Mates

Are you looking for a colorful and fun fish to add to your micro or nano aquarium? Do you want to add some color to your community aquarium? If you answered yes to any of the questions above, consider the clown killifish, one of the most stunning fish around.

In general, clown killifish aren’t too difficult to care for and keep, and because of their small size, they are a great choice for smaller aquariums. If you have a micro or nano tank like 5-gallon tank and intend to keep clown killifish, you may wonder “how many clown killifish in 5 gallon”.

In this article, I will answer that question. I will also discuss the ideal conditions of their tank in order to ensure you provide them with an optimal environment and compatible tank mates.

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Clown Fish Review

  • Care Level: Easy
  • Temperament: Peaceful
  • Diet: Omnivore
  • Water Conditions: Freshwater, tropical
  • Max Size: around 1.5 inches
  • Lifespan: 3 to 5 years

What You Should Keep In Mind When Stocking A 5-gallon Tank? 

It is not only important that you know what fish species you will be able to keep in your 5-gallon aquarium but there are a few other factors that you should take into account as well.

As the first aquarium for new hobbyists, a small aquarium may be the most appealing choice. Small tanks are often attractively designed, will fit neatly onto a countertop or desktop, and are often considerably less expensive to purchase than larger ones.

However, a nano tank is generally defined as a freshwater aquarium that has a capacity of fewer than 10 gallons, which severely limits your options. Only a few fish species have the ability to thrive in a very small tank, and even fewer of them will do well in that size tank. And I do want to emphasize the word thrive here. Certainly, there are quite a few species of fish that can live in a nano tank, but very few of them are going to be happy in such a setup and will remain healthy.

Clown Killifish Tank Conditions

Clown Killies occupy the top section of the tank
Clown Killies occupy the top section of the tank

Clown Killifish can be kept in a micro tank or nano tank. They are small enough so that you can keep multiple of them in such a small aquarium. In addition, you can also house them in a community tank that is already inhabitants in the bottom and middle of the tank. At that point, the Clown Killies will be able to occupy the top part of the tank.

Small and large tanks both have their benefits and drawbacks. It should be noted that clown killifish will not reproduce as much if they are kept in a langer tank with other fish species. So, if you were hoping to get Clown Killifish fry, you might want to opt for the smaller, dedicated tank rather than the larger one.

Small tanks, however, often have a strong filter that creates too much strong current for Clown Killies.

Alternatively, you could use a planted tank instead of a filter. The setup that uses plants instead of filter are advantageous for a number of reasons: the plants help maintain a clean tank; they provide a covered area for Clown Killifish to lay their eggs; they provide cover for fry, and they provide hiding places for the shy adults Clown Killifish. 

Water Sprites, Java Ferns, Guppy Grass, and Water Lettuce are good plant choices. Driftwood is also beneficial for clown killifish.

Water Conditions

Clown Killifish live in soft, warm, acidic water in the wild, so you will want to recreate these conditions in your home aquarium if you wish to keep them in it. 

The water can be preconditioned prior to adding the fish. Add the tank water to a separate container and soak the peat for a few days in the box filter. There will be a slight amber tint to the water, this is perfectly suitable for Clown Killifish.

A closer match to their natural habitat is best achieved by these parameters:

  • pH levels: 4-7
  • Water hardness: 4-8 dKH
  • Water temperature: 68° – 79° F (20° – 26° C)

Filter Or No Filter

The Clown Killifish prefer still water, so you should use a gentle filter or use lots of plants instead
The Clown Killifish prefer still water, so you should use a gentle filter or use lots of plants instead

The Clown Killies prefer still water, so if you don’t have a filter, you should perform a 50-percent water change every few days. Additionally, you should ensure that your aquarium has enough plants in it so that they can absorb ammonia and nitrates that would otherwise harm the fish. Your fish will remain healthy if your aquarium is kept clean.

In case you use a filter, make sure to put lots of plants or decorations in front of it to prevent direct flow that will stress the Clown Killifish. In addition to this, you should choose a gentle filter with low flow, so the water won’t be moved too much.

Clown Killifish Tank Size

In the case that you have a dedicated Clown Killifish tank, a micro tank or a nano tank of at least 5 gallons will be sufficient. A smaller tank has the disadvantage that fairly strong filters are needed to keep the tank clean but Clown Killies do not like strong currents.

Unless you have a dedicated Clown Killifish tank, you’re going to have to get a larger tank in order to accommodate all your fish. When Clown Killies are kept in a community tank, breeding may be hindered.

How many clown killifish in 5 gallon? 

In any case, Clown Killifish are not schooling fish, but they tend to do better when they are in groups of their own. With consideration of their small maximum size and swimming behavior, I would say that you can comfortably place 5 clown killifíh in a 5-gallon tank. 

Clown Killifish Tank Mates

If you are not planning a dedicated tank for these tiny fish, then it is best to select small and peaceful fish to pair with Clown Killies. 

You should consider some suitable tankmates for your clown killifish: 

  • Bettas
  • Corydoras Catfish
  • Danios
  • Gouramis
  • Minnows
  • Small Barbs
  • Small Plecos
  • Some Varieties Of Tetras

Because the Clown Killifish will occupy the top part of the tank, it’s a good idea to choose the mid-level and bottom feeders to go with them. 

Lastly, small shrimp or snails can also be good tankmates due to their contribution to keeping the water clean by consuming leftover food and detritus. Additionally, make sure you choose tankmates that are as happy in still or slow-moving water as the clown killifish are. If you want to keep all creatures living in your tank in good health, you have to ensure they have the right environment and water conditions in order to thrive and prosper.

Video About Adding Clown Killifish To Nano Aquarium


Can we keep killifish in pairs?

While most killifish are peaceful fish that get along well with other fish in community tanks, it is important to be aware that males have a tendency to show aggression towards each other. Due to this, if you are a beginner, it is recommended that you only keep a pair of killifish in a species-only aquarium.

How many killifish should be kept together?

 If you intend to keep killifish together, you should keep at least 3 of them together with a ratio of female to male of 2:1. It is possible to keep up to 12 individuals in larger tanks (30+ gallons in size).

Are clown killifish aggressive?

No, clown killifish are not aggressive. This is a peaceful fish that is best kept in small groups with an even number of clown killifish (they pair up naturally). These are passive and social fish that school together.


So, to answer the question “how many clown killifish in 5 sallon?”, 5 fish is my recommendation. 

To ensure that they live in good health and thrive, only caring about the number of fish in the tank is not enough, you will also have to keep their tank conditions ideal and make sure that they are paired with compatible tanks. 

By following the tips and rules outlined in this article, you should have no problems.

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