How To Care For Zebra Danio (Zebrafish)

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Oregon State University, CC BY-SA 2.0, via Wikimedia Commons

The Zebra Danio or Zebrafish, which is scientifically known as the Danio rerio is one of the most beautiful fish species that is loved by many fishkeepers all over the world. It is a freshwater fish species from the Minnow (Cyprinidae) family. Its common trade name is Zebra Danio, and the most common name is Zebrafish, and the reason behind this name is that this fish has black and white lines that stretch from head to lateral fins. The native region of this fish is South Asia, and it is commonly found in rivers, lakes, and ponds all across the India and Pakistan border region. It is found in tropical and subtropical regions but is mostly considered a tropical fish species.

There are multiple reasons for its popularity in the west, apart from being a favorite fish among fishkeepers, it is also one of the fish species that are used in scientific research. A lot of pharma companies test medicines on these fish species first and then clear them for human experimentation. In scientific circles, it is known as the model vertebrate organism, but the fishkeepers love it for its beautiful colors, and ability to survive. It is also easy to breed in captivity, and that is also why many new fishkeepers prefer having it in their aquariums, as they can learn about breeding fish using them.

Basic Facts Table:

LifespanAverage 5 years in ideal conditions, 1 to 2 years in the wild.
SizeAverage 4cm(1.6 inches) but some can reach 5cm (2 inches)
ColorsBlackish/Bluish-Purple and Silver-Gold Stripes
Freshwater or SaltwaterFreshwater
Care LevelMinimum, good for new to fishkeeping
CompatibilitySocial, Good for community aquariums but should be paired with peaceful and small fish species.

Tank Companions:

The Zebrafish is a small fish species, it is social and good for community aquariums. But it is a shy and peaceful species. That is why you should only pair the Zebrafish with other small, social, and peaceful fish species. Otherwise, they would either get eaten or get bullied if you paired them with the wrong companions. Here is a list of the ideal companions that you should put in the same tank as the Zebrafish or Zebra Danio fish.

  • Rosy Barbs
  • Rummy Nose Tetras
  • Bronze Cories
  • Honey Gourami
  • Ember Tetra
  • Celestial Pearl Danio
  • Emerald Pufferfish
  • Neon Tetra
  • Dojo Loaches and other peaceful loaches.
  • Snails
  • Freshwater Shrimps.

You should never keep them in the same tank with fish species that have long fins. These include Sailfin Molly Fish and Elephant Ear Guppies. Your Zebra Danio fish would eat their fins. There are instances where these species have successfully and peacefully lived in aquariums, but in most cases, Zebrafish nip at the long fins of other fish. Also, as mentioned earlier, it is a peaceful fish species and also has a small size and cannot defend itself if attacked. That is why you should not pair it with any predator fish species such as Redtail Catfish, or any other large predatory fish species.


The Zebra Danio or Zebrafish is a small fish species. In the wild conditions, they only grow up to 1.8–3.7 cm (0.7–1.5 in). But in aquariums where the conditions are perfect for their growth, they can grow up to 4–5 cm (1.6–2.0 in). Their body contains five stripes of bluish/black color which occur due to pigmentation in their body. These stripes go from head to tail and when the fish moves, it gives a vivid appearance of changing colors depending on the light conditions. The body of the fish has a silver-gold color which also appears in the shape of stripes but it also covers the head, and most of the fins as well. The shape of this fish species is fusiform but the lateral portion of the body is compressed.

Their mouths are directed upwards, instead of downwards, indicating that they do not like to forage on the ground. The male and female in this species have different shapes of bodies, which helps the breeders identify the male and female correctly. This leads to better pairing and more chances of success at breeding them. The shape of the male body is similar to a torpedo, and the body contains gold stripes between the blue/blackish stripes. Meanwhile, the shape of a female body in this species is longer and their bellies are white instead of golden. The adult females in this species also have a small genital papilla that covers the anal fin.

There are also some naturally occurring albino Zebra Danio fish. They have similar body shapes but they lack the pigmentation, hence lacking the stripes, and colors in their bodies. In the wild, this is one of the rare occurrences, but in the fishkeeping industry, it is a common practice to specially breed them for their beauty.

Origin and Natural Habitat:

The Zebra Danio or Zebrafish is native to the freshwater areas of South Asia, including Pakistan, India, Nepal, Bhutan, and Bangladesh. It is found in rivers, lakes, ponds, and other freshwater sources. They range from the Sutlej river basin in Pakistan to Arunachal Pradesh in the India-Pakistan-China border region near the Himalayas. The Zebra Danio or Zebrafish is also found in the Ganges and  Brahmaputra river basin area. It is also found in some areas in Myanmar towards East Asia regions and found in the border region in Bangladesh. It is one of the few fish species that are found in such a large area. It is because they have developed a lot of techniques to avoid extinction.

Their natural habitat helps them to survive the conditions. For example, most of the river basin areas in these countries consist of slow-moving water bodies that support the population of Zebra Danio or Zebrafish. Zebra Danio fish populations can survive in harsh conditions because they are very good at breeding. They breed every year and produce a lot of offspring which helps them restore their numbers. Also, the water in their natural habitats is soft, contains fewer minerals, and has a slow-moving flow. This creates a perfect environment for them in these areas to help them survive.

Zebra Danio (Zebrafish) Lifespan:

The Zebra Danio or Zebrafish can live for up to five years, provided that the conditions are optimal for their growth. In the wild, they only live for a year or two and become prey to other larger fish species. But as they lay a lot of eggs, the new fish restore the balance of the population. The average age or lifespan for this species is about 2 to 3 years in captivity. You can enhance this lifespan by providing your fish with favorable conditions to live. If the conditions favor their health, they can live more than four to five years.

Habitat and Tank Conditions:

To provide the Zebra Danio fish with favorable conditions you will have to make sure that the tank conditions are similar to that of their natural habitat. It would allow them to live peacefully and reach their potential size and lifespan. Also, your fish would remain healthy only if the tank conditions are perfect. To create the perfect habitat in the tank for the Zebra Danio fish, you should start from the bottom layer of the tank. They are not bottom feeders, but they occasionally go there. That is why you will also have to focus on making that part of the tank according to their needs.

In the bottom layer of the tank, you should spread some fine, soft sediment such as treated sand. It would work the best for the Zebrafish as their natural habitat contains soft sand in the bottom layer. The second thing that you will add to this part is the substrate. Make sure to wash all the substrate before putting it in the tank, there is a chance that it might contain pathogens or even mud inside and that could contaminate the water. Washing it would help you get rid of those and will make it clean.

The next thing that you should do is to put some plants inside the container. There are a lot of freshwater plants that you can put in the aquarium. But you should prefer the ones that grow in the middle layer of the tank. You can put plants such as Aqua ferns and Amazon sword plants. You can also add ornaments and other things that you want to add such as a filtration pump. This would keep the water inside the tank fresh, and would also produce some flow. The grass inside the tank would provide them with plenty of space to hide and play and would also act as a food source as they also eat vegetation.

Make sure to use proper lights above their aquarium as the Zebra Danio fish or Zebrafish do not like the dark environments. Also, make sure that lights are not too bright for them. 12 hours of light exposure is better as it would replicate the natural cycle of light day and night. To endure the rocky bottom look inside the tank, you can also put round rocks inside. While creating the aquarium, make sure that you do not put anything in the aquarium that can harm the fish. For example, avoid using plastic-based ornaments with openings wide enough to trap the fish inside. You may also have to use a controlled heater to maintain water temperature inside the tank.

Water Conditions:

The water conditions inside the tank would determine the health of your Zebra Danio fish. That is why they need to be perfect to favor their growth. You can create a perfect environment for the Zebrafish to grow by replicating their natural habitat water conditions. They need a lot of water, at least 10 gallons per fish. So, make sure that your tank is big enough to contain that much water. Here are the other water conditions that should be followed while creating a perfect aquarium for the Zebra Danio or Zebrafish.

  • The recommended temperature inside the tank is 64°F to 82°F
  • pH recommendation for water is 6.5 to 7.5 (try maintaining neutrality as much as possible)
  • The recommended hardness of water is 8 to 12 KH.
  • The minimum tank size is 20 gallons for two Zebrafish.
  • Make sure about 20 to 25% of water is filtered every week.

As you can see from these recommendations, they are offering a wide range of options. That means it is to create an environment and maintain it. Also, if there are a few fluctuations in the water conditions, it would not affect their health that much. Which makes them an ideal choice for those fish keepers who are new to fishkeeping. Their small mistakes would not cause the death of these fish. It would give them time to learn about maintaining a perfect environment inside the tank.

Water Source:

The tap water that we mostly use in our households comes from water filtration plants. To make this water usable and to kill harmful bacterias inside it, chemicals such as chlorine are added to the water. This makes the water unusable for the aquarium as the chlorine and other chemical additives might impact the health of the fish. You will have to filter the tap water before putting it inside the fish tank.

Also, if you are buying water for the fish tank, you should avoid buying mineral water as it contains a lot of minerals and additives. You should buy distilled water that is specifically prepared for the fish tanks. It contains the exact amounts of minerals that you need. You will not have to distill or filter this water before putting it in the aquarium. But if this is not a viable option for you, you can use the tap water but you will have to clean it before putting it in the tank. You can also use RO water and RO/DI water for the fish tanks.

Ideal Size For The Tank:

The minimum size of the tank for the Zebrafish is 10 gallons, but you will have to have a bigger tank if you want to create a community aquarium with other fish. You will need to know the number of fish that you want to keep in that aquarium, it will help you know the exact size of the tank that you need. A single Zebra Danio fish needs at least 2 gallons of water so, a ten-gallon tank will be good only for keeping 5 Zebra Danio individuals. But if you want to put more fish in your aquarium, you should add 2 gallons per fish that you are adding.

For example, if you want to have 15 fish, make sure that your water container can contain at least 30 gallons of water. It is always better to use a bigger tank for keeping your fish as it will help you when you want to add more fish in the future. Not only that, a bigger tank would be able to contain more water, hence providing more space for Zebrafish to explore, and wander around. If you add more fish in the water than the recommended amount, you will have to deal with overcrowding issues. So, make sure that you get a large tank that can contain as much water as you need according to the number of fish you are planning on putting in that container.

Behavior and Temperament:

The Zebrafish are known for their joyful and social behavior. Also, they exhibit shoaling behavior and like to move around with other members of their group. They stay in the group and follow the leader, which they usually decide in a non-aggressive playful manner. The Zebrafish can get along with other fish species of small size and social nature and show no aggression towards most. But they do attack some of the long-finned species. That is why it is recommended to not keep them in the same tank as long-finned species.

According to research, they do not like being alone as it can induce tension, and stress which can lead to the illness and death of the Zebrafish. That is why it is better to keep them in a community of fish or atleast have two or three fish of the same species in a tank. Large shoals of these fish can become hyperactive and you will see them moving from one part of the tank to another almost all the time. So, it is advised to keep the size of the shoal small. Most of the time they like to live in the middle layer of the water, but they also visit the upper layer and the bottom layer of the aquarium.

Breeding Zebra Danio (Zebrafish):

As mentioned earlier, it is one of those fish species that are easy to breed in captivity. Both males and females have different body shapes, sizes, and coloring. That helps you identify the male and females correctly so that you can pair them. They breed in the monsoon season. To induce breeding behavior in the Zebrafish, you will have to change the temperature inside the tank.

You will have to create a separate breeding tank of about 5 to 10 gallons capacity. This would help you breed successfully and prevent the eating of eggs by other fish in the tank. Raise the temperature a little about 77 to 81 F. Make sure to feed both males and females before the process begins. You will notice that the female body has started to change as it grows round indicating the presence of eggs inside. Feed the male and female for about two weeks so that eggs can grow inside the female body.

Put two males with each female inside the breeding tank, and let the spawning begin. Females would lay eggs, (white are infertile eggs and blackish eggs are fertile) in the bottom of the tank. After this, you should remove the male and female from the breeding tank. It is important to remove them otherwise they would try to eat the eggs and the breeding process would fail. After that, let the eggs be in the breeding time and let them hatch.

Eggs and Fry Care Guide:

After fertilization of eggs, they hatch and fry within 72 hours. First, fry eats the egg sacks but after that, you will have to provide them special food that is good for the fry. You can use powdered fry food or infusoria. Do not place them inside the adult tank yet, wait for a few weeks. Once they have gained enough size that they would not be bullied by the larger fish. You can place them inside their parents’ tank. It is better that you create a separate tank for the fry so that all members of their community are of the same age and size. Also, it would help you avoid overcrowding in their parents’ tank.

Diet of Zebra Danio:

The diet of Zebra Danio or Zebrafish is omnivorous. It is what helps them survive in the wild conditions as they eat a variety of foods that are easily available in their environment. In aquariums, you should feed them live animals and pellet food. You can feed them algae-based flakes, zucchini, cucumbers, shelled peas, spinach, and other vegetables. Make sure that these items are either crushed into powder or flake. You can provide them with live food such as daphnia and bloodworms once a week. It would help you maintain the right balance in their feed. Use small pinch-sized food portions as they will be easy to consume. Also, feed them more than twice a day.

Diseases of Zebra Danio:

The Zebra Danio or Zebrafish is known as one of the most durable species due to its better immune system. It is protected from many common fish infections such as Ich. but they are susceptible to some other diseases. Here is a list of the diseases that can attack your Zebra Danio fish.

  • Mycobacteriosis: It is known as one of the worst diseases in fish as it is most difficult to get rid of. It is caused by Mycobacteria. You can detect this disease by checking the fish for infections on the skin, inflammation, anorexia, lethargy, and fin loss. If these conditions appear in your fish, you should separate it from the other and replace the water immediately. It is because it is one of the most contagious diseases and it can kill an entire aquarium. You can not treat this disease with normal methods and medications of fish treatment. The only current solution to this problem is to quarantine the diseased individuals, change the water, and disinfect the entire tank. But if this does not help, you will have to get rid of the entire stock and restart.
  • Velvet Disease: It is caused by dinoflagellate parasites, and is also known as gold dust. If any of your fish get infected, their skin would change into dusty gold color. You can get rid of this by cleaning your water, warming it for a few days, using aquarium salt, and putting copper sulfate in the water.
  • Nematode Infection: It is an infectious disease found in nematodes. This infectious disease can also kill your fish. The easy way to treat this problem is by identifying the infected members and putting them in quarantine and using fish medications.

Most of these infectious diseases occur in the Zebrafish community only if the water is contaminated. So, keeping the water clean and maintaining the required temperature would help you avoid these problems.

Is Zebra Danio a Saltwater or Freshwater Species?

The Zebra Danio fish is a freshwater species found in South Asia (Pakistan, India, Nepal, Bhutan, Bangladesh, and some areas of Myanmar.). It is found in freshwater, slow-moving river basins, ponds, and lakes.

Is Zebra Danio a Schooling Species?

Yes, the Zebra Danio or Zebrafish is a schooling species. The ideal school size for this species is about 6 individuals. They would move around together and dart from one part of the tank to another behind a leader. If the school size is larger, they would become a hyperactive fish species and that would be a problem for other fish in a community aquarium. So, you should make sure that you keep the school size to a minimum limit.

How Many Zebra Danio Fish Should Be Kept Per Gallon of Water?

The ideal environment to favor the growth and health of Zebra Danio fish requires that each individual must be kept in 2 gallons of water. 1 Zebrafish = 2 gallons of water.

Conclusion – Is Zebra Danio Suitable For Your Aquarium?

Yes, if you are a fan of peaceful fish species that dart from one part of the aquarium to another with their school, you should get them. They are also a good choice for the new fish keepers as they are a durable fish species. They can live through a few mistakes that a new fishkeeper might make. Apart from that, they have one of the most beautiful shapes and body-color patterns. Their unique coloring and stripes make them beautiful to look at. Also, they are easy to take care of and manage. Keeping the above points in mind, it can be said that yes, they are a very suitable fish for your aquarium.


Question: How many Zebra Danio in a 5-gallon tank?

Answer: You can keep 2 Zebra Danio fish in a 5-gallon tank, but it is not a recommended size and you should avoid using it. You should use a ten-gallon tank (recommended minimum tank size) to keep five fish.

Question: What is the ideal temperature for a Zebra Danio tank?

Answer: The ideal temperature for the Zebra Danio tank is between  64°F to 82°F or 17.77 °C to 27.7 °C. Maintaining temperature at this level will help you keep your fish healthy.

Question: What is the size of Zebra Danio?

Answer: In the wild, the size of Zebra Danio is about 1.8–3.7 cm (0.7–1.5 in). Meanwhile, in perfect conditions, they can grow up to 5cm or two inches.

Question: How to breed Zebra Danio?

Answer: You can breed Zebra Danio in monsoon season. Before spawning, feed the male and female for two weeks to prepare for breeding. After that, put two males and one female in separate tanks. Females would lay eggs and males would fertilize them. After that remove the adults and let the eggs hatch and feed the fry appropriate fry food.

Question: What is the ideal KH for Zebra Danio Tank?

Answer: The ideal KH in a Zebra Danio tank is between 8 to 12 KH.

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