Killifish Ultimate Care Guide, Size, Diet, Breeding, Tankmates & All |2022

By: Martin McAdam
Updated: April 3, 2022

Killifish is a very popular fish for both beginners and experienced aquarists alike. They are small fish, making them an ideal choice for a small aquarium, and they come in a variety of colors, some of which can be quite striking. There are many different types of Killifish, so it is important to do your research before purchasing one to ensure that it will be compatible with your other fish.

Killifish are not particularly difficult to care for, but there are a few things to keep in mind. They are very sensitive to water quality, so regular water changes and filtration are necessary. They also prefer to live in groups, so purchasing at least three or four is best.

In this guide, we will cover the basics of how to care for Killifish. We will discuss the tank size, water parameters, diet that they require, and how to deal with common problems.

So, without further ado, let's get started!

Scientific name:Aphyosemion
Common name:African Killifish, killi
Family:Aplocheilidae
Size:1-2 inches (2.5-5 cm)
Life span:3 months to 5 years (Species Dependent)
Habitat:Killifish are found in Africa, South America, and Central America
Behavior:Killifish are schooling fish and should be kept in groups of three or more
Tank size:20 Gallons per pair
Water temperature:68-75 degrees Fahrenheit
ph Range:6.8-7.6
Water hardness:Hard to soft
Water Type:Freshwater
Activity level:Moderate
Compatibility:Usually peaceful, but can be aggressive towards other fish of the same species
Tankmates:Many, but avoid fish that are larger than the Killifish
Care Level:Easy
Diet:Carnivore, but can be trained to eat flake food

Species Summary

The Killifish is a proud member of the Aplocheilidae family and is found in the warm climates of Africa, South America, and Central America. These fish get their common name because they are known to kill and eat smaller fish.

The Killifish is a schooling fish, so it is best to keep them in groups of three or more. They are peaceful fish, but they can be aggressive towards other fish of the same species. They should not be kept with larger fish than they are, as they may become prey.

Size & Growth Rate

As far as size goes, Killifish generally only grows about 1-2 inches (2.5-5 cm) long. However, some species can get up to 6 inches (15 cm) in length.

As for the growth rate, this will vary depending on the species of Killifish. Some species grow quickly, while others grow more slowly.

However, Killifish will generally grow about an inch (2.5 cm) per year.

Lifespan

The average Killifish lifespan is around 2-5 years in an aquarium. Left in the wild, this fish's lifespan would be much shorter due to predation and disease. If you want your fish to live a long life, it is important to provide them with the best care possible.

Appearance

Killifish come in a wide variety of colors and patterns, making them some of the most beautiful fish in the aquarium hobby. Some common colors include red, blue, yellow, green, and black. They also come in various patterns, including spots, stripes, and blotches.

Like almost every other fish, the males are usually more brightly colored than the females. The males also tend to be smaller than the females. Females are typically drab in coloration and grow to be larger than males.

The tops of these fish's heads are often different from the rest of their bodies. This is known as the "eyespot" and is used to attract mates. The fish's mouth sits low on its head, and its eyes are located on the sides of its head. Its teeth are generally small and pointed, perfect for catching small prey.

The vast majority of Killifish have two anal fins. However, there are a few species that only have one. So, if you're unsure whether your fish has one or two anal fins, it's best to consult a professional. The fins of a Killifish can be a great indicator of its age – the longer and more filamentous the fins, the older the fish.

Males and females of most species can be told apart by their fins. Males usually have longer and more filamentous fins than females, while females often have shorter and less showy fins.

Behavior & Temperament

For the most part, Killifish are peaceful fish. They can be kept with various other fish, as long as the other fish are not too large. They are also not known to be particularly territorial.

However, there are some exceptions. Male Killifish can be aggressive towards each other during spawning season. If you have multiple males in your tank, you may need to separate them during this time.

Spawning season for Killifish typically lasts from May to September. During this time, the males will become increasingly aggressive towards each other. If you have multiple males in your tank, you may need to separate them during this time.

When it comes to temperament, Killifish are generally peaceful fish. However, there are some exceptions. Male Killifish can be aggressive towards each other during spawning season. If you have multiple males in your tank, you may need to separate them during this time.

Breeding Killifish

Killifish are a popular fish for breeding. To breed Killifish, you will need to have a tank at least 20 gallons in size. Water temperature should be 68-75 degrees Fahrenheit.

In order to trigger spawning, you will need to provide the fish with plenty of hiding places. This can be done by adding plants or other decorations to the tank. You will also need to ensure that the water is clean and well-filtered.

Once the fish are ready to spawn, the male will chase the female around the tank. The female will lay her eggs in a suitable spot, and the male will then fertilize them. The eggs will then hatch within a few days.

The fry will need to be fed a brine shrimp or baby formula diet until they are big enough to eat other food. They should be kept in a separate tank until they are big enough to be placed in the main tank. As they grow, you will need to increase the size of the tank slowly.

Breeding Killifish is not a complex process, but it does require some planning and preparation. If you are interested in breeding Killifish, do your research beforehand. This will help to ensure that your fish are healthy and happy.

What Are The Different Types of Killifish

There are well over 1270 species of Killifish, so it would be impossible to go over them all in this care guide. However, we will cover some of the more common and widespread species that are kept as pets.

Some of the more common and widespread species include the

  • Clown Killifish
  • Least Killifish
  • Golden Wonder Killifish
  • Gardneri Killifish
  • Blue Gularis Killifish
  • Bluefin Killifish
  • Striped Killifish
  • Dusky Killifish
  • Pygmy Killifish
  • Mangrove Killifish
  • Gulf Killifish
  • Lampeye Killifish
  • Rainwater Killifish

Clown Killifish

The Clown Killifish is one of the most popular species of Killifish. They get their name from their bright and colorful markings, which resemble those of a clown. They are very hardy fish and can tolerate a wide range of water conditions.

Least Killifish

The Least Killifish is a small and colorful fish often kept as a pet. They are one of the smallest species of Killifish, reaching only about 1 inch (2.5 cm) in length. They are hardy fish and can tolerate a wide range of water conditions. Least Killifish are peaceful fish and should not be kept with larger fish than they are.

Golden Wonder Killifish

The Golden Wonder Killifish is a beautiful and widespread species of Killifish. They get their name from their bright golden coloration.

Gardneri Killifish

The Gardneri Killifish is a popular and beautiful species of Killifish. They are named after the American ichthyologist Dr. Carl L. Gardner, who first described the species.

Blue Gularis Killifish

The Blue Gularis Killifish is a popular and beautiful species of Killifish. They are named after the blue coloration of their gular plates (the bones in their throat).

Bluefin Killifish

The Bluefin Killifish is a popular and beautiful species of Killifish. They get their name from their bright blue coloration.

Striped Killifish

The Striped Killifish is a popular and beautiful species of Killifish. They get their name from the stripes that run along their body.

Dusky Killifish

The Dusky Killifish is a popular and beautiful species of Killifish. They get their name from the dusky coloration of their body.

Pygmy Killifish

The Pygmy Killifish is a popular and beautiful species of Killifish. They get their name from their small size.

Mangrove Killifish

The Mangrove Killifish is a popular and beautiful species of Killifish. They get their name from the mangrove trees that they live in.

Gulf Killifish

The Gulf Killifish is a popular and beautiful species of Killifish. They get their name from the Gulf of Mexico that they live in.

Lampeye Killifish

The Lampeye Killifish is a popular and beautiful species of Killifish. They get their name from the lampeye fish that they resemble.

Rainwater Killifish

The Rainwater Killifish is a popular and beautiful species of Killifish. They get their name from the rainwater pools that they live in.

The Essentials To Killifish Care

Killifish care is not difficult, but there are a few things that you need to know to keep your fish healthy and happy.

Killifish are carnivores and require a diet high in protein. They can be fed a variety of live and frozen food. They need a place to hide and rest. Provide them with some rocks or plants to help them feel secure.

Killifish reproduce very quickly, so it is important to monitor the size of your aquarium to ensure that there is enough room for all the fish.

They are very sensitive to changes in water quality, so it is important to do regular water changes and keep the aquarium clean. Killifish are not known for being long-lived fish, so enjoy them!

Tank Size

Because of their need for high oxygen levels, Killifish should be kept in relatively small tanks. A 20-gallon tank is a minimum size for a single Killifish. Larger tanks can be used, but be sure to provide plenty of aeration.

When setting up your tank, be sure to use a good quality filter and maintain good water quality. Killifish are very sensitive to changes in their environment, and even small fluctuations can be fatal.

Water Parameters

The ideal pH for Killifish is between 6.5 and 7.5. The ideal hardness is between 4 and 8 dGH. The ideal temperature is between 68-75 degrees Fahrenheit.

However, the vast majority of Killifish can tolerate a pH range of 5.5 to 8.5, a hardness range of 2 to 30 dGH, and a temperature range of 68 to 86 degrees Fahrenheit (20-30 degrees Celsius).

New fish owners should not try to change their water's pH, hardness, or temperature. It is best to let the fish adjust to the conditions in their new tank. To stay healthy and happy, Killifish need a lot of oxygen. Be sure to use a good quality filter and maintain good water quality.

The aquarium water should be changed regularly, about 25% every week. These fish require more attention than some other species, but they are well worth the effort!

Filtration

When choosing a filter for your Killifish tank, be sure to get one appropriate for your aquarium's size. A good rule of thumb is to choose a filter that will turn over the entire volume of your tank at least once per hour.

Killifish are very sensitive to changes in water quality, so it is important to do regular water changes and keep the aquarium clean.

Some recommended filters for Killifish tanks include:

Canister filters: Canister filters are an excellent choice for Killifish tanks. They are very efficient and can be hidden inside the aquarium, making them less obtrusive.

Internal filters: Internal filters are a good option for small or nano tanks. They are easy to install and maintain and do not take up a lot of space.

Hanging filters: Hanging filters are a good option for larger tanks. They hang on the back of the aquarium and can be hidden behind plants or other decorations.

Power filters: Power filters are a good choice for all types of aquariums. They are easy to install and maintain, and they provide good filtration.

Heating

Killifish need a warm environment to thrive. The ideal temperature for their tank is between 68 and 75 degrees Fahrenheit.

However, the vast majority of Killifish can tolerate a temperature range of 68 to 86 degrees Fahrenheit (20-30 degrees Celsius).

If your home is cooler than this, you will need to provide some additional heat for your Killifish tank. A heater is a must for keeping tropical fish healthy.

Some recommended heaters for Killifish tanks include:

Submersible heaters: Submersible heaters are a good choice for all types of aquariums. They are easy to install and can be placed inside the tank, making them less obtrusive.

Hanging heaters: Hanging heaters are a good choice for larger tanks. They hang on the back of the aquarium and can be hidden behind plants or other decorations.

Powerhead heaters: Powerhead heaters are a good choice for all types of aquariums. They are easy to install and can be placed inside the tank, making them less obtrusive.

Lighting

Killifish need a lot of light to thrive. The ideal lighting for their tank is bright but not too harsh.

Some recommended lights for Killifish tanks include:

Fluorescent lights: Fluorescent lights are a good choice for all types of aquariums. They provide good lighting without being too harsh.

LED lights: LED lights are a good choice for all types of aquariums. They are energy-efficient and provide good lighting without being too harsh.

Halogen lights: Halogen lights are a good choice for larger tanks. They provide bright, intense light that can be beneficial for plants.

Co2 Systems

Killifish need a lot of oxygen to stay healthy and happy. Be sure to use a good quality filter and maintain proper water quality. The aquarium water should be changed regularly, about 25% every week.

Some recommended CO2 systems for Killifish tanks include:

Pressurized CO2 systems: Pressurized CO2 systems are a good choice for all types of aquariums. They are easy to install and provide constant CO2 levels.

Non-pressurized CO2 systems: Non-pressurized CO2 systems are a good choice for larger tanks. They are more difficult to install, but they do not require much maintenance.

Substrate

Killifish do not need a lot of substrate in their tank. A layer of gravel or sand is required to provide them with a comfortable place to rest.

Some recommended substrates for Killifish tanks include:

Gravel: Gravel is a good choice for all types of aquariums. It is easy to install and maintain and provides a natural look.

Sand: Sand is a good choice for all types of aquariums. It is easy to install and maintain and provides a natural look.

Rock: Rock is a good choice for all types of aquariums. It is easy to install and can be used to create a natural look in the tank.

Aquascaping

Aqua scaping is the art of arranging plants and other decorations in an aquarium to create a beautiful and natural-looking landscape.

Killifish are an excellent choice for aquascaping because they are small and colorful.

Some recommended aquascaping plants for Killifish tanks include:

Water sprite: Water sprite is a good choice for all types of aquariums. It is easy to grow and provides a beautiful, natural look.

Java Fern: Java fern is a good choice for all types of aquariums. It is easy to grow and provides a beautiful, natural look.

Bacopa: Bacopa is a good choice for all types of aquariums. It is easy to grow and provides a beautiful, natural look.

Anubias: Anubias is a good choice for all types of aquariums. It is easy to grow and provides a beautiful, natural look.

Decorations

Killifish do not need a lot of decorations in their tank. A few plants and a few pieces of driftwood or rocks are required to provide them with a comfortable place to rest.

Some recommended decorations for Killifish tanks include:

Driftwood: Driftwood is a good choice for all types of aquariums. It is easy to install and provides a natural look.

Plants: Plants are a good choice for all types of aquariums. They provide good cover for the fish, and they can also help to filter the water.

Other Tank Accessories

There are a few other things that you will need to get for your Killifish tank. These include a thermometer, a ph meter, and an air pump.

Thermometer: A thermometer is important to have in your tank. It will help you monitor the water temperature and make sure that it is within the correct range.

Ph Meter: A ph meter is important to have in your tank. It will help you monitor the water's pH level and make sure that it is within the correct range.

Air Pump: An air pump is important to have in your tank. It will help to keep the water oxygenated and provide a healthy environment for the fish.

You can create a healthy and happy home for your Killifish by following these tips. With a little bit of care and attention, they will thrive in your aquarium.

Water Changes

Water changes are an important part of taking care of your Killifish. You should do a water change every week, replacing about 25% of the water.

When changing the water, you should:

  • Use a siphon to remove the water from the tank.
  • Rinse the gravel with clean water.
  • Refill the tank with clean, treated water.

After you have finished the water change, you should check the water parameters to ensure they are within the correct range.

Cleaning The Tank

Cleaning the tank is an essential part of taking care of your Killifish. You should clean the tank every month, which means removing all of the decorations and scrubbing the sides of the tank.

  • When cleaning the tank, you should:
  • Remove all of the decorations from the tank.
  • Scrub the sides of the tank with a brush.
  • Rinse the gravel with clean water.
  • Refill the tank with clean, treated water.
  • Add a de-chlorinator to the new water.

After you have finished cleaning the tank, you should check the water parameters to ensure they are within the correct range.

Cleaning The Filter

Cleaning the filter is an essential part of taking care of your Killifish. You should clean the filter every month, removing all of the media and rinsing it with clean water.

When cleaning your filter, be sure to:

  • Remove all of the media from the filter.
  • Rinse it with clean water.
  • Reinstall the media in the filter.

Some recommended filter media for Killifish tanks include:

  • Activated carbon.
  • Biological media.

After you have cleaned the filter, you should check the water parameters to make sure that they are within the correct range.

Testing The Water

Testing the water is an essential part of taking care of your Killifish. You should try the water every week, using a water test kit to check the pH level, ammonia level, nitrite level, and nitrate level.

If any of these levels are not within the correct range, you should do a water change and adjust the dosage of your water treatment.

You can create a healthy and happy home for your Killifish by following these tips. With a little bit of care and attention, they will thrive in your aquarium.

Common Possible Diseases

There are a few common disease symptoms that you should be aware of. If your Killifish show any of these symptoms, you should take them to a veterinarian immediately:

  • Loss of appetite.
  • Swelling around the eyes or gills.
  • Reddening or fading of the colors.
  • Clamped fins.
  • Lethargy.
  • Flashing (rubbing their body against objects in the tank)

And there are a few diseases that are common in Killifish. Some of these diseases include:

  • Flukes: Flukes are parasitic flatworms that can infest fish's gills, skin, and fins. They are typically transmitted by infected water or food.
  • Ich: Ich is a type of parasitic protozoan that can infest the skin and gills of fish. It is typically transmitted by infected water or food.
  • Fin Rot: Fin Rot is a bacterial infection that attacks the fins and tail of fish. It is typically transmitted by infected water or fish.
  • Velvet: Velvet is a type of parasitic protozoan that can infest the skin and gills of fish. It is typically transmitted by infected water or food.

If you think that your fish may be sick, it is important to immediately take them to a veterinarian.

Preventing Diseases

There are a few things that you can do to help prevent disease in your Killifish. Some of these things include:

  • Quarantine new fish for at least two weeks before adding them to your tank.
  • Do not overfeed your fish.
  • Keep your tank clean and well-maintained.
  • Do not add fish to your tank that is not compatible with Killifish.
  • Do not stress your fish.

By following these tips, you can help prevent disease in your Killifish. A timely diagnosis and treatment can often save the life of your fish.

Treatment And Medications Of Diseases

A few different medications can be used to treat diseases in Killifish. Some of these medications include:

  • Antibiotics: Antibiotics are a type of medication that is used to treat bacterial infections.
  • Anti-Parasitic Drugs: Anti-Parasitic Drugs are a type of medication that is used to treat parasitic infections.
  • Antifungal medications: Antifungal medications are a type of medication that is used to treat fungal infections.
  • Medicated Foods: Medicated Foods are a type of food that is used to treat diseases in fish.

With a little bit of care and attention, your Killifish can live a long and healthy life. By following the tips, you can provide them with the best possible care.

Food & Diet

Killifish are carnivorous, so they should be fed a diet that consists mostly of meat-based foods. Some good food choices for Killifish include:

  • Bloodworms: Bloodworms are a type of worm that is high in protein and fat. They are an excellent food choice for Killifish.
  • Brine shrimp: Brine shrimp are a type of crustacean high in protein and fat. They are an excellent food choice for Killifish.
  • Krill: Krill are a type of small shrimp high in protein and fat. They are an excellent food choice for Killifish.
  • Daphnia: Daphnia is a type of small crustacean high in protein and fat. They are an excellent food choice for Killifish.
  • Tubifex worms: Tubifex worms are a type of worm that is high in protein and fat. They are an excellent food choice for Killifish.

It is also good to supplement their diet with some plant-based foods. Some good choices for plant-based foods include:

  • Algae wafers: Algae wafers are a type of food that is high in fiber and protein. They are a good choice for supplementing the diet of Killifish.
  • Vegetables: Vegetables are a good source of fiber and vitamins. They can be used to supplement the diet of Killifish.

While Killifish can survive on a diet that consists mostly of meat-based foods, it is also important to provide them with some plant-based foods. This will help ensure that they get the essential nutrients to stay healthy.

You can also feed them a variety of commercially prepared fish foods, such as:

  • Flake food: Flake food is a type of fish food that is made from dried and compressed fish flakes. It is an excellent food choice for Killifish.
  • Pellets: Pellets are a type of fish food that is made from compressed pellets of fish meal. They are an excellent food choice for Killifish.
  • Frozen foods: Frozen foods are an excellent food choice for Killifish. They are typically high in protein and fat, ideal for carnivorous fish like Killifish.

However, it is important to note that not all commercially prepared foods are suitable for Killifish.

Diet Foods To Avoid

When choosing a diet food for your Killifish, it is important to avoid foods high in carbohydrates. Some examples of high carbohydrate foods include:

  • Bread: Bread is a type of food that is high in carbohydrates. It should be avoided when feeding Killifish.
  • Potatoes: Potatoes are a type of food that is high in carbohydrates. They should be avoided when feeding Killifish.

It is also important to avoid feeding your Killifish foods high in salt. Some examples of high salt foods include:

  • Kosher salt
  • Table salt
  • Sea salt

Feeding your Killifish a diet that is high in carbohydrates or salt can lead to health problems, such as obesity and heart disease.

Feeding Schedule

How often you should feed your Killifish will depend on the age of the fish and the type of food that you are providing them. Generally, you should feed them a small amount of food two to three times a day. However, you can feed them a larger amount once a day. when feeding them live food or frozen food

It is also important to note that you should not overfeed your Killifish. Overfeeding can lead to health problems, such as obesity and heart disease. If your fish seem to be overeating, you may want to reduce the amount of food that you are feeding them.

When it comes to feeding your Killifish, it is important to find a schedule that works best for you and your fish. Try to stick to a consistent feeding schedule and be sure not to overfeed your fish. With a little trial and error, you should be able to find the perfect feeding schedule for your Killifish.

Tank Mates

Killifish are naturally peaceful fish. They can be kept with a variety of other fish, as long as the other fish are not too large. They are also not known to be particularly territorial.

Some good tank mates for Killifish include:

  • Danios: Danios are a type of fish that is known to be peaceful. They make good tank mates for Killifish.
  • Guppies: Guppies are another type of fish known to be peaceful. They make good tank mates for Killifish.
  • Mollies: Mollies are another type of fish known to be peaceful. They make good tank mates for Killifish.
  • Platies: Platies are a type of fish known to be peaceful. They make good tank mates for Killifish.
  • Neon Tetra: Neon Tetras are a type of fish known to be peaceful. They make good tank mates for Killifish.
  • Green Neon Tetra: Green Tetras are a type of fish known to be peaceful. They make good tank mates for Killifish.

When choosing tank mates for your Killifish, it is important to choose fish known to be peaceful. This will help to avoid any conflict in the tank. Try to stick with fish that are the same size or smaller than your Killifish. Avoid fish that are known to be territorial.

Some bad tank mates for Killifish include:

  • Bettas: Bettas are a type of fish known to be aggressive. They should not be kept with Killifish.
  • Goldfish: Goldfish are a type of fish known to be aggressive.
  • Cichlids: Cichlids are a type of fish known to be aggressive. They should not be kept with Killifish.

Advantages Of Having Them In Your Tank

  • The first advantage of having Killifish in your tank is that they are peaceful fish. This means that they will not get into fights with other fish in the tank. They also do not require much maintenance, making them a good choice for beginner aquarium owners.
  • Killifish are also a popular fish for breeding. If you are interested in breeding fish, Killifish is a good choice. They are relatively easy to breed, and they do not require a lot of space.
  • Another advantage of having Killifish in your tank is that they are known to be disease-resistant. This means that they are less likely to get sick than other fish. Killifish are also known to be very hardy, meaning that they can survive in various water conditions.

If you are looking for a peaceful and easy-to-care-for fish, Killifish may be the right choice. They are disease-resistant and hardy, making them an excellent choice for both beginner and experienced aquarium owners.

Disadvantages Of Having Them In Your Tank

Although Killifish is a peaceful and easy-to-care-for fish, they have some disadvantages in your tank. One drawback is that they are known to be jumpers. This means they may jump out of the tank if it is not covered.

Another disadvantage of Killifish is that they are not suitable for all types of tanks. They require a tank that is at least 20 gallons in size. If you do not have a large tank, Killifish may not be the right fish.

Conclusion

Killifish are a popular fish for both beginner and experienced aquarium owners. They are peaceful and easy to care for, making them a good choice for those who are new to fishkeeping.

They are also known to be disease-resistant and hardy, meaning that they can survive in various water conditions. Although Killifish have some disadvantages, such as being jumpers and not being suitable for all tanks, they are an excellent choice for those who are looking for a peaceful and easy-to-care-for fish.

So, if you are interested in breeding Killifish, be sure to do your research beforehand. This will help to ensure that your fish are healthy and happy.

Thanks for reading!

Disclaimer

AquaMarinePower.com does not intend to provide veterinary advice. We go to great lengths to help users better understand their aquatic friends. However, the content on this blog is not a substitute for veterinary guidance. For more information, please read our disclaimer.

Amazon Associates Program

AquaMarinePower.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

Copyright © 2021 AMP
cross