Mastering Killifish Care: Tank Setup, Water Quality, Diet, Breeding, Diseases & More!

If you’re looking for a unique and colorful fish to add to your aquarium, you might want to consider keeping killifish. These fish are known for their vibrant colors and interesting patterns, but they also require specific care to thrive. In this article, I’ll cover the basics of killifish care, including tank setup, water quality, tank mates, diet, common diseases, breeding, and more.

Killifish require a well-maintained aquarium with suitable water conditions, a varied diet, and a peaceful environment. The specific water requirements depend on the species of killifish. The aquarium should be decorated with hiding places, and regular water changes should be performed to ensure their health. They are peaceful and social fish, making them an excellent choice for community tanks.

When I first started keeping killifish, I was surprised to learn how much attention they require compared to other fish I’ve owned. For example, they need a specific water chemistry to stay healthy, including soft water with a low pH. They also need plenty of hiding places, as they can be shy and easily stressed. But with the right setup and care, killifish can be a rewarding and fascinating addition to your aquarium.

In this article, I’ll share my experience with killifish care and provide tips and advice for keeping these unique fish happy and healthy. Whether you’re a seasoned fish keeper or new to the hobby, I hope you’ll find this guide helpful and informative.

Killifish Care

Species Summary

If you’re considering adding killifish to your aquarium, it’s important to know a bit about their background and characteristics.

Here’s a brief summary of what you need to know:


Killifish are found in a variety of habitats around the world, from streams and rivers to swamps and marshes.

They’re particularly common in Africa and South America, but can also be found in North America, Europe, and Asia.


On average, killifish live for about 2-3 years. However, with proper care and attention, some species can live for up to 5 years.


Killifish come in a wide range of colors and patterns, making them a popular choice for aquarium enthusiasts.

They typically have elongated bodies with pointed heads and fins that are either rounded or pointed. Their scales can be smooth or patterned, and some species have distinctive markings on their bodies.


The size of killifish varies depending on the species, but most are relatively small.

They typically range from 1-4 inches in length, with some species growing up to 6 inches long.

Growth rate

The growth rate of killifish can vary depending on their environment and diet.

In general, they grow fairly quickly and can reach their full size within a year or two.

Behavior & Temperament

Killifish are generally peaceful and can be kept with other non-aggressive fish.

However, they can be territorial with members of their own species, so it’s important to provide plenty of hiding places and space in the aquarium. They’re also known for jumping, so it’s important to keep the tank covered.

Male vs Female

Male and female killifish can be distinguished by their fins and coloration. Males typically have more vibrant colors and longer fins, while females have shorter fins and are less brightly colored.

Some species also have distinctive markings on their bodies that can help differentiate between males and females.

Personally, I’ve found killifish to be fascinating and beautiful additions to my aquarium. With the right care and attention, they can thrive and add a unique touch to any tank.

Tank Setup

Setting up a tank for your killifish is an important part of ensuring they stay healthy and happy.

Here are some key factors to consider when setting up your killifish tank:

Tank Size

When it comes to killifish, size matters. They require a tank that is at least 20 gallons, but ideally, a tank that is 30 gallons or larger is recommended.

This will provide enough space for your killifish to swim around and establish territories. Keep in mind that killifish are jumpers, so a tight-fitting lid is essential to prevent any escapes.


Killifish prefer dim lighting, so it’s important to choose a light that is not too bright. A timer can be used to control the amount of light your killifish receive each day.

This will help mimic their natural habitat and keep them healthy.


A good filtration system is essential for maintaining water quality in your killifish tank.

A hang-on-back filter or canister filter is recommended, as they provide good water flow and are easy to maintain. It’s important to keep up with regular filter maintenance to prevent any issues with water quality.


Killifish require oxygen-rich water, so aeration is important.

An air pump and air stone can be used to provide oxygen and increase water flow, which will help keep your killifish healthy.


Killifish are tropical fish and require a water temperature between 72-78 degrees Fahrenheit.

A heater can be used to maintain a consistent water temperature in your killifish tank.


A sandy substrate is recommended for killifish, as it mimics their natural habitat. Avoid using gravel, as it can trap debris and make it difficult to maintain water quality.


Killifish enjoy having hiding places in their tank, so adding decorations such as caves or driftwood can provide them with a sense of security.

Be sure to choose decorations that are safe for your killifish and won’t harm them.


Live plants can provide many benefits for your killifish tank, such as oxygenation and natural filtration.

Java moss and Anubias are great plant options for killifish tanks, as they are hardy and can tolerate low lighting conditions.

Overall, setting up a tank for your killifish requires careful consideration of their specific needs.

By providing them with a suitable environment, you can ensure that your killifish will thrive and live a long, healthy life.

Killifish Care 2

I remember when I first set up my killifish tank, I was so excited to create a beautiful and healthy environment for my fish.

It took some trial and error, but with the right equipment and attention to detail, my killifish have been thriving ever since.

Water Quality

pH Levels

Maintaining the proper pH level is crucial for the health of your killifish. The ideal pH range for killifish is between 6.0 and 7.5.

I personally keep my killifish at a pH of 7.0, which has worked well for me. It’s important to note that sudden changes in pH levels can be stressful for your fish, so make sure to monitor and adjust pH levels gradually.


Killifish are tropical fish and require a water temperature between 72-82°F. I keep my tank at a steady temperature of 78°F.

It’s important to use a reliable aquarium thermometer to monitor the temperature and make adjustments as necessary.

Water Hardness

Killifish prefer soft to moderately hard water with a hardness level between 5 and 12 dGH. I personally keep my water hardness around 8 dGH.

It’s important to note that some killifish species have specific water hardness requirements, so be sure to research the needs of your particular species.

Water Changes

Regular water changes are essential for maintaining good water quality and healthy fish. I recommend changing 10-20% of the water in your killifish tank once a week.

This will help remove any accumulated waste and replenish essential minerals and nutrients. When doing water changes, make sure to use a dechlorinator to remove any harmful chemicals from tap water.

Overall, maintaining good water quality is crucial for the health and well-being of your killifish.

By monitoring and adjusting pH levels, temperature, water hardness, and performing regular water changes, you can ensure your fish thrive in their environment.

Tank Mates

Compatible Fish Species

When it comes to choosing tank mates for your killifish, it’s important to pick species that share similar temperaments and environmental preferences.

Some compatible fish species that can live peacefully with killifish include:

  • Tetras
  • Guppies
  • Platies
  • Mollies

I personally keep my killifish with tetras, and they get along great.

It’s important to note that even with compatible species, it’s still important to monitor your tank for any signs of aggression or stress.

Incompatible Fish Species

On the other hand, there are some fish species that should not be kept with killifish due to their aggressive nature or differing environmental needs.

Some incompatible fish species include:

Fish SpeciesReason for Incompatibility
CichlidsAggressive and territorial
GoldfishRequire colder water temperatures
BarbsCan nip at fins and cause stress

It’s important to research any potential tank mates before adding them to your killifish tank.

By choosing compatible species and avoiding incompatible ones, you can create a peaceful and thriving aquatic community.

How Many Killifish Should Be Kept Together?

Killifish are a type of freshwater fish that come in many different species, with varying sizes, colors, and temperaments.

As a general rule, the number of killifish that can be kept together depends on the size of the tank, the species of killifish, and the purpose of keeping them.

For a 10-gallon tank, it is recommended to keep 3-4 killifish, although this number can vary depending on the species.

Some smaller species, such as the Nothobranchius guentheri, can be kept in larger groups of up to 10 individuals.

On the other hand, larger species, such as the Aphyosemion australe, may require more space and fewer individuals.

For a larger tank, such as a 30-gallon or 50-gallon tank, the number of killifish that can be kept together can increase.

Some species, such as the Fundulopanchax gardneri, can be kept in groups of up to 12 individuals, while others may require fewer individuals due to their size or temperament.

When keeping killifish, it is important to maintain a proper male-to-female ratio for breeding purposes. The ideal ratio is usually 1:3, with one male and three females.

This allows for natural breeding behavior and helps to prevent aggression between males.

In addition, killifish are highly active fish that require plenty of swimming space and hiding places.

It is recommended to provide plenty of plants, rocks, and other decorations to create a suitable environment for them. It is also important to keep a lid on the tank to prevent the fish from jumping out.

Overall, the number of killifish that should be kept together depends on the size of the tank, the species of killifish, and the purpose of keeping them.

It is important to do research on the specific species of killifish and their requirements before deciding on the number of fish to keep.


Feeding your killifish a balanced diet is crucial for their health and longevity. In this section, I will discuss feeding frequency and types of food that are suitable for your killifish.

Feeding Frequency

As a general rule, you should feed your killifish small amounts of food multiple times a day.

I recommend feeding them two to three times a day, but adjust the frequency based on your fish’s appetite and behavior.

Overfeeding can lead to health problems, so it’s important to monitor your fish’s eating habits.

Types of Food

Killifish are omnivores, which means they eat both plant and animal matter. Their diet should consist of a variety of foods to ensure they receive all the necessary nutrients. Here are some types of food that are suitable for your killifish:

  • High-quality flake or pellet food
  • Frozen or live foods such as brine shrimp, bloodworms, and daphnia
  • Vegetables such as spinach, zucchini, and cucumber

It’s important to provide your killifish with a varied diet to prevent them from becoming bored with their food. I like to rotate their diet every few days to keep things interesting.

Additionally, make sure to remove any uneaten food from the tank to maintain good water quality.

When I first started keeping killifish, I struggled to find the right balance of food. I found that feeding them too much caused them to become lethargic and bloated, while not feeding them enough led to stunted growth.

But with some trial and error, I found the perfect feeding routine for my killifish. Remember, every fish is different, so it’s important to observe their behavior and adjust their diet accordingly.

Common Diseases


I’ve been keeping killifish for a while now, and I’ve learned that they are generally hardy fish. However, they are still susceptible to a few diseases.

One of the most common diseases that killifish can get is ich, which is caused by a parasite. Another disease that killifish can get is fin rot, which is caused by bacteria.


If you notice that your killifish are scratching themselves against objects in the tank, or if you see white spots on their body, then they might have ich.

If you notice that your killifish’s fins are frayed or that they have white or red patches on their fins, then they might have fin rot.


If you suspect that your killifish have ich, then you should raise the temperature of the tank to 86°F for a few days. You should also add aquarium salt to the tank, as this can help kill the parasite.

If you suspect that your killifish have fin rot, then you should do a water change and add an antibacterial medication to the tank. In my experience, prevention is always better than treatment.

To prevent diseases in your killifish, make sure that you maintain good water quality and avoid overfeeding.

Also, quarantine any new fish that you add to the tank to prevent the introduction of diseases.

Remember, if you notice any signs of disease in your killifish, it’s important to act quickly to prevent the disease from spreading to other fish in the tank.

Signs of a Healthy Killifish

As a killifish owner, it is important to know the signs of a healthy fish. Here are a few things to look out for:

  1. Active and alert behavior: A healthy killifish will be swimming around the tank, exploring its environment, and interacting with other fish.
  2. Bright and vibrant coloration: Killifish come in a variety of colors, but a healthy fish will have a bright and vibrant coloration that is consistent throughout its body.
  3. Clean and clear eyes: The eyes of a healthy killifish should be clear and free of any cloudiness or discoloration.
  4. Healthy fins and scales: A healthy killifish will have fins that are fully extended and free of any tears or damage. Its scales should be smooth and shiny.
  5. Good appetite: A healthy killifish will have a good appetite and eagerly eat its food.

It is important to note that these are just general signs of a healthy killifish. If you notice any changes in your fish’s behavior, appearance, or appetite, it may be a sign of illness or disease.

Always monitor your fish closely and consult with a veterinarian or experienced fish keeper if you have any concerns.

Personally, I have found that my killifish are happiest and healthiest when I provide them with a clean and well-maintained tank. Regular water changes, proper filtration, and a balanced diet are all important factors in maintaining the health of your killifish.

Overall, keeping a close eye on your killifish and providing them with a healthy environment will help ensure that they live a long and happy life.

Signs of a Sick Killifish

As a killifish owner, it’s important to know the signs of a sick fish. Here are a few things to look out for:

  1. Loss of appetite – If your fish is not eating, it could be a sign of illness.
  2. Discoloration – If your fish’s colors are fading or changing, it could be a sign of stress or disease.
  3. Erratic swimming – If your fish is swimming erratically or struggling to swim, it could be a sign of swim bladder issues or other health problems.
  4. Clamped fins – If your fish’s fins are clamped against its body, it could be a sign of stress or illness.
  5. Rapid breathing – If your fish is breathing rapidly or gasping for air, it could be a sign of poor water quality or other health issues.

If you notice any of these signs in your killifish, it’s important to take action quickly. The first step is to test your water quality to make sure it’s within the proper parameters.

If the water quality is good, you may need to quarantine the sick fish and treat it with medication.

Personally, I’ve had a killifish that stopped eating and became lethargic. After testing the water quality and finding no issues, I quarantined the fish and treated it with medication. Within a few days, the fish was back to its normal self and eating again.


Breeding killifish can be a rewarding experience for any aquarist. It’s important to ensure that the breeding setup is suitable, and that the eggs and fry are well taken care of.

Breeding Setup

Killifish Care 3

When setting up a breeding tank for killifish, it’s important to ensure that the water conditions are optimal. The water temperature should be between 72-78°F, with a pH of 6.0-7.0.

A substrate of fine sand or peat moss can be used, along with plenty of plants for the fish to lay their eggs on. It’s also important to provide plenty of hiding places for the fish, such as caves or PVC pipes.

Egg Incubation

Once the eggs have been laid, they can be removed from the breeding tank and placed in a separate container for incubation.

The container should be filled with water from the breeding tank, and kept at a temperature of around 75°F. It’s important to ensure that the water is well oxygenated, either by using an air stone or by gently agitating the water.

Fry Care

Once the eggs have hatched, the fry should be fed small amounts of food several times a day. Baby brine shrimp or microworms are good options for feeding fry.

It’s important to keep the water clean and well oxygenated, and to ensure that the fry have plenty of hiding places to help them feel secure.

I have found that breeding killifish can be a very rewarding experience. It’s important to ensure that the breeding setup is suitable, and to take good care of the eggs and fry.

With a little bit of patience and dedication, it’s possible to successfully breed these beautiful fish.

Product recommendations for Killifish:

  1. Hikari Micro Pellets: This fish food is specially formulated for small fish like Killifish and contains high-quality ingredients to promote growth and vibrant colors.
  2. API Aquarium Test Kit: This kit allows you to test the water quality of your aquarium, which is essential for keeping Killifish healthy.
  3. Marineland Penguin Power Filter: This filter is designed for aquariums up to 50 gallons and provides mechanical, chemical, and biological filtration.
  4. Aqueon Aquarium Heater: This heater is fully submersible and can maintain a consistent temperature in your aquarium.
  5. Seachem Flourish Excel: This liquid fertilizer provides essential nutrients for plants in your aquarium, which Killifish love to swim around.
  6. Zoo Med Floating Betta Log: This floating log provides a hiding place for your Killifish and adds some visual interest to your aquarium.
  7. Tetra Whisper Air Pump: This air pump creates a stream of bubbles in your aquarium, which can help to oxygenate the water and create a more natural environment for your Killifish.
  8. Fluval Plant and Shrimp Stratum: This substrate is designed for planted aquariums and provides a natural environment for your Killifish to thrive in.
  9. Hikari Freeze Dried Bloodworms: These freeze-dried bloodworms are a great treat for Killifish and can be fed as a supplement to their regular diet.


After spending many years caring for killifish, I can confidently say that they are a rewarding and fascinating species to keep. With proper tank setup and water quality, along with a varied and nutritious diet, killifish can thrive and bring joy to any aquarium enthusiast.

It is important to remember that killifish are not a beginner species, and require some experience and knowledge to care for properly. Additionally, it is crucial to research and carefully consider tank mates before introducing them to your killifish tank.

Common diseases can be prevented with regular water changes and proper tank maintenance. If you do notice any signs of illness, it is important to act quickly and seek help from a qualified veterinarian or aquatic specialist.

Finally, breeding killifish can be a rewarding experience, but it requires patience and dedication. By providing the right environment and conditions, you can successfully breed and raise healthy killifish fry.

All in all, I highly recommend killifish as a unique and fascinating addition to any aquarium. With proper care and attention, they can thrive and bring joy for many years to come.

Personally, I have found that watching my killifish swim and interact with each other is incredibly calming and therapeutic. It is a joy to see them thrive and grow under my care, and I highly recommend this species to anyone looking for a rewarding and engaging aquarium experience.


As a killifish enthusiast, I often get asked a lot of questions about caring for these beautiful fish. Here are some of the most frequently asked questions:

Q: What size tank do I need for my killifish?

A: Killifish can thrive in a tank as small as 10 gallons, but I recommend a tank of at least 20 gallons to provide ample swimming space. Keep in mind that some species of killifish require more space than others, so research your specific species to determine their needs.

Q: What water parameters should I maintain for my killifish?

A: Killifish are adaptable to a wide range of water conditions, but generally prefer slightly acidic to neutral water with a pH between 6.0 and 7.5. Water temperature should be kept between 72°F and 78°F. Regular water changes are important to maintain good water quality.

Q: Can killifish be kept with other fish?

A: Yes, but it’s important to choose tank mates carefully. Killifish are peaceful fish, but can be territorial towards other fish of the same species. Avoid keeping them with aggressive or fin-nipping fish. Good tank mates for killifish include tetras, rasboras, and other peaceful community fish.

Q: What should I feed my killifish?

A: Killifish are omnivores and will eat a variety of foods. A high-quality flake or pellet food can make up the bulk of their diet, but be sure to supplement with live or frozen foods such as brine shrimp, bloodworms, and daphnia. Avoid overfeeding, as killifish have a tendency to become obese.

Q: What are some common diseases that affect killifish?

A: Killifish are generally hardy fish, but can be susceptible to diseases such as ich and velvet. Keeping the water clean and maintaining good water quality can help prevent these diseases. Quarantining new fish before adding them to your main tank can also help prevent the spread of disease.

Q: How do I breed killifish?

A: Breeding killifish can be a rewarding experience. Many species of killifish are annuals, meaning they have a short lifespan and lay their eggs in the substrate to hatch later. To breed killifish, provide a breeding tank with plenty of hiding places and a substrate for the eggs. Keep the water slightly acidic and at a temperature between 72°F and 78°F. Once the eggs are laid, remove the adults from the tank to prevent them from eating the eggs. The eggs will hatch in a few weeks and the fry can be fed newly hatched brine shrimp or other small foods.

Reference: Wikipedia.


Hi there! My name is Jacob, and I'm the founder of this Pet people blog that talks all about aquarium and fishkeeping. I've been passionate about fish and aquatic life since I was a kid, and I've spent countless hours learning about different species, their habitats, and how to create the perfect environment for them to thrive in.

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