Killifish 5 Gallon Tank: A Good Choice For Your Home

Deciding on the right size fish tank for your home is essential. A 5-gallon tank is a popular choice for many people. They’re small enough to fit in most homes but large enough to house a few fish. Killifish are a popular type of fish to keep in these tanks. They’re known for being hardy and easy to care for. If you’re thinking about getting a killifish, here’s what you need to know about “killifish 5 gallon”. Let’s scroll down to find out!

Can Killifish Live In A 5-Gallon Aquarium?

Freshwater fish are a popular pet choice for many people, but it is essential to research which type of fish is best for your home and lifestyle before making a purchase. If you are looking for a small fish that can live in a 5-gallon aquarium, killifish may be a good option. These little fish are hardy and can adapt to different water conditions, making them ideal for beginner fish keepers.

How Many Killifish 5 Gallon You Can Keep?

A standard fish tank
A standard fish tank

In theory, as long as you have a large enough tank to fit a number of killifish in, you can keep as many of them together as you like.

With that stated, male killifish may be rather hostile against other male killifish, especially during the breeding season and when they lack sufficient space to dwell appropriately.

Hence, if you want multiple killifish together, for example, four of them, only one should be a male. When you follow the 2 gallons of water per fish rule discussed above, a male to female ratio of 3 to 1 should allow you to avoid problems with aggression.

Is It Necessary For Killifish To Be Paired Up?

In theory, killifish are not schooling fish, so they can be kept by themselves if necessary. In nature, however, it is safer to have some of one’s species around both for some company and because in numbers, we are safer.

So, it’s best if you get at least three or four killifish and house them together in your aquarium. When they are paired with tank mates from their species, they will be much happier.

What Type of Killifish Is Best For A 5 Gallon Tank?

The killifish is a freshwater fish that is becoming increasingly popular in the home aquarium. These fish are known for their vibrant colors and exciting patterns. There are many different types of killifish, but not all of them are suitable for a 5-gallon tank. This section will introduce the killifish types that can live well in this environment.

Clown Killie

General Info: 

  • Care Requirements: Simple
  • Temperament: Calm and collected
  • Diet: I’m an omnivore.
  • Water Freshwater and tropical climates are required.
  • 1 inch is the maximum size.
  • 3 to 5 years is the expected lifespan.

Clown killifish may be placid, but they are predators. The doves wait along the water’s edge rather than chasing after their prey. Clown-killing insects capture unsuspecting insects with their raised jaws as they skim the surface.

Least Killifish 

General Info: 

  • Beginner’s level of care
  • Temperament: Calm and collected
  • Diet: I’m an omnivore.
  • Water Freshwater and tropical climates are required.
  • Size ranges from 1 to 1.4 inches in height.
  • Life expectancy is 3 to 4 years.

Keeping least killifish in groups of at least four individuals is the best way to ensure a healthy population of this species. These little fish enjoy a well-planted aquarium with plenty of hiding spots.

You won’t find these adorable tiny fish in aquarium stores very often, but you can get them for a reasonable price from internet sellers such as eBay, Amazon, Petco, etc. 

Housing Requirements For Killifish

To ensure your killifish thrive, you must meet housing requirements. These include tank shape, water condition, lightning, substratum, decoration, filtration, and plenty of plants. Keep reading to find out in detail.

Tank Shape

There are various tank shapes for you to choose
There are various tank shapes for you to choose

Stocking any tank requires careful consideration of the shape of the aquarium. Aquariums shaped in squares, cubes, or tall hexagons are a great deal more difficult to stock and decorate than long rectangular aquariums.

Keeping fish in vases and bowls is not recommended. In both styles of containers, the water surface area and the amount of space are very limited, and thus the dissolved oxygen levels in the water are typically low. 

This is detrimental to any organisms that reside within the container. Furthermore, it is tough to filter water properly in a bowl, resulting in poor water quality and high fish mortality. If you are looking for a tiny aquarium, I recommend choosing a rectangular tank.

Water Condition

As a subtropical fish, killifish prefer relatively warm, but not excessively warm, water temperatures to thrive in.

Keep in mind that the exact temperature at which the water should be heated will vary depending on the individual variety of killifish.

For the most part, temperatures ranging from 68 to 75 degrees Fahrenheit should be fine, with most killifish able to survive in water temperatures as low as 72 degrees Fahrenheit.

If this is the case, you will almost certainly want a good aquarium heater as well as an aquarium thermometer to keep track of the temperature.

Aeration And Filtration

Aeration is beneficial for killifish, as they prefer a high concentration of dissolved oxygen in the water. If you have a tiny tank, an air pump and/or airstone are advised. As a result, these fish are extremely sensitive to the water quality in which they live.

You’ll want a water filter that utilizes mechanical, biological, and chemical filtration methods. It is suggested that an aquarium filter with a flow rate of 30 gallons per hour or more be used for a 10-gallon killifish tank. It’s essential to bear in mind that these fish aren’t fans of strong or even moderate currents.

Hence, a rear trickle or waterfall filter on a hanger is suggested. These reduce the flow of water in the tank, and they can also aid in the aeration of the water.

The Lighting

On bright lights, killifish are not enormous. Indeed, they prefer that their aquariums remain rather dark. They should not be overly black, but neither should they be excessively brilliant. A typical aquarium lamp with a low output will suffice for this fish.


The substrate is one of the most vital factors when building a tank
The substrate is one of the most vital factors when building a tank

It is best to have a mixture of sand and aquatic peat moss as the substrate for killifish. When they reproduce, these fish need soft sand or peat moss to lay their eggs in and bury them. These fish enjoy exploring the bottom of the tank and searching for food.

Indeed, you can put them on a very fine gravel substrate, though they might not feel really at home, and their chances of reproducing will also be greatly reduced.


As a rule, killifish like to swim through and hide in vegetation with a reasonable amount of growth. One problem here is that many aquarium plants require a considerable amount of light, while killifish do not like bright light. Because of this, you will need to choose plants that thrive in low lighting conditions.

The java moss, java ferns, and other cryptocorynes also make good choices. The Java moss is especially useful for breeding purposes since killifish can lay their eggs in it.

Additionally, many individuals choose to offer their killifish a few floating plants to serve as cover from above.


In addition to rocks, hollow caverns, driftwood, and pottery, killifish enjoy having a couple of these items nearby. They’re always up for a good adventure, but they also like a little privacy now and then. A tiny cave and a piece of hollow driftwood are advised for a small killifish aquarium.

Youtube: Set Up 5-Gallon Tank


How hard is it to keep Killifish?

The killifish is an ideal aquarium fish for beginners because of its easy breeding and care. This fish is unquestionably elegant, and the way it spawns is fascinating. Among its few disadvantages, the beginner must wait a few months between the first spawning and the first hatching, as with many other annuals.

Are killifish compatible with bettas?

The answer is no; killifish cannot live with betta fish. When kept in the same tank with bettas, killifish eggs and fry are a tasty snack for bettas, and if they are kept together, they will probably become aggressive towards each other.

What’s the ideal number of killifish to keep together?

The killifish thrive when kept in close proximity to each other. I recommend keeping at least three of them together (1 male and two females). Large tanks (30 gallons or more) can accommodate as many as 12 individuals who will learn together.

In Conclusion

In conclusion, a 5-gallon tank is an excellent choice for a beginner fish keeper. It is the perfect size for a variety of fish and can be accommodated in a variety of locations. The cost of this tank is also very affordable, making it a great option for those on a budget. A 5-gallon tank can provide its owner with proper care and maintenance for many years of enjoyment.

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