Zebra Danio: Species Profile

Category: Danios

Common Names: Zebra Danio

Scientific Name: Danio rerio

Family: Cyprinidae

Minimum Tank Size: 10 Gallons

Care Level: Easy

Temperament: Peaceful

Max Size: 3 Inches

Temperature: 64-78 F

pH: 6.5-8.0

Tank Level: Middle to Top

Colors: Blue, Black, Purple, Silver, Yellow

Diet: Omnivore

Breeding: Easy

Macro photo of a zebrafish (Danio rerio) with a white background

Zebra Danio Overview

The Zebra Danio (Danio rerio), also referred to as the Zebrafish, is a popular freshwater fish for novice and expert hobbyists alike.

They’re famous among scientists who study the Danio rerio species and are one of the most frequently used model organisms used for genetics and development studies. Surprisingly, Zebrafish have similar organs and tissues as humans and share 70% genes with us.

Scientists also use Zebrafish to model various diseases like cancer, heart diseases, kidney disease and Alzheimer’s.

They come from the Cyprinidae family, more commonly known as the minnow family. Like other species in this family, they have lateral stripes from their heads to their tails.

There are many advantages to choosing Zebrafish as an addition to your aquarium. These hardy fish are easy to care for, non-aggressive and can withstand various water conditions.

Zebra Danio are great fish for beginners and are readily available in just about any pet shop. Although the rerio is a small fish, it’s hard to miss it with its bright blue and white stripes. The animal is also a playful breed that’ll spend its days happily swimming around the tank.

Distinguishing Features of the Zebra Danio

Zebra Danios are famous for their blueish-purple iridescent stripes across their bodies. The five lines start from the side of their heads and go to their tail.

The base color of their bodies may be white, gold or silver hues. Zebrafish have torpedo-shaped bodies and upturned mouths, making it easy to eat food from the top of the tank.

Although Zebra Danio fish are eye-catching on their own, between naturally occurring mutations and artificial selection by breeders, you can find other Zebrafish morphs, including:

  • Long Fin Zebra Danio: Zebra Longfin Danios are long-finned varieties scientists developed through selective breeding. It has a similar appearance to the standard wild Zebrafish but with more extended and elegant fins.
  • Albino Zebra Danio: Albino Danios are naturally occurring color morphs you can find in their wild habitats. These fish have some transparency to them with a pink or cream hue. However, they are often bred in captivity as well.
  • Golden Zebra Danio: Golden Zebra Danios, also known as Gold Zebrafish or Gold Danios, are bred within the aquarium industry. As the name suggests, they have a golden yellow-orangish color similar to that of a goldfish.
  • Leopard Zebra Danio: Leopard Danios are one of the easiest of this species to pick out of a school. Unlike most Zebrafish, Leopard Danios have spots rather than stripes. Its leopard-like areas are blue-gray on top of an overall gold-brown metallic body. There is also a longfin variety of the Leopard Zebra Danio.
  • GloFish Danio: Scientists who worked with fluorescent protein genes taken from sea coral created the GloFish. You can spot these eye-catching fish in bright neon colors like green, orange, red, purple, and blue. You can also observe the same bright neon colors in other fish species, such as tetras.
  • Transparent Zebra Danio: Scientists created the Transparent Zebra Danio morph to observe diseases more easily in Zebrafish for the sake of research.

Zebra Danio in Black Background

Origin of the Zebra Danio

Scientists once theorized that Zebrafish originated from west Pakistan to Myanmar in the east. As they continue to develop more studies, they now believe Zebra Danios come from parts of India and Bangladesh.

The misconception that these fish came from such a wide array of locations comes from mistaking another species for the Danio rerio. Additionally, environmental damage has eliminated several habitable areas in the wild.

Zebrafish typically live in stagnant waters of ponds, streams, ditches, rice paddies and shallow canals. Sometimes they live in fast-moving streams, though that is less common.

They have lots of vegetation in their natural habitat, some of which are submerged or hanging into the water from banks.

Their natural water bottoms are either sandy, muddy or rocky.

Average Zebra Danio Sizes

Typically, Zebra Danios at pet stores will be under an inch in length, and they won’t get much bigger. At maturity, they only reach an average of 1.5 to 2 inches.

Some Zebrafish will reach 2.5 inches, and there are even limited reports of the fish reaching 3 inches in length.

Because ponds have more room to swim around and contain larger supplies of natural food sources, the Danio rerio may be larger if in a pond.

Lifespan of the Zebra Danio

Zebrafish only live for about a year when in their natural habitat. However, if you take good care of your fish and maintain a healthy environment, they may live to be over five years old.

On average, Zebra Danio lives to be 2-5 years, so there is no guarantee that your fish will be five even under the best care. If you give your fish a nutrient-dense diet and keep up with cleaning the tank, you’ll have a better chance of more years with your pet.

Conversely, poorly managed aquariums may lead to disease in your fish, which can cause premature death.

Zebra Danio with Red Tint

Male vs. Female Zebra Danio

Male and female Zebrafish both have the same five stripes and two barbel pairs. Males are smaller and slimmer than females, and females will have a thicker belly when pregnant.

Temperament of Zebra Danio

Zebra Danio fish are social fish that will actively swim around their enclosure. They have a shoaling behavior, and owners should keep the animal in a fish community.

They may become stressed, ill or less active when left alone. They’re peaceful pets and do well with other fish.

If alone, add a few fish to their tank. You’ll see them have a burst of energy and be happier fish overall. While they prefer spending time at the top of the aquarium, they’ll explore the whole environment.

They should have at least five other fish in their community, but more is always better. Within the group of fish, Zebra Danios will establish a hierarchy so they will play, chase and harmlessly nip at each other.

Although they do well with most fish, they may especially nip at long-fin fish that move slowly throughout the tank.

Zebra Danio Tank Parameters

Zebra Danio is one of the best fish for beginners due to their ease of care. You can keep them in an indoor aquarium or outdoor pond.

Minimum Tank Size

The tank size will depend on the number of fish you plan to own. If you start with five fish, you’ll need a bigger tank if you add in more.

For five fish, you’ll need a minimum of a 10-gallon tank. With each new Zebrafish you add to the enclosure, go up in size by two gallons.

Water Parameters

Zebra Danios live in both fast-moving streams and stagnant ponds in the wild, though they prefer some slow-moving water. They should have plenty of areas to hide while also having space to swim around in the open.


Although they are technically cold-water fish, they prefer to live in 79-83 degrees Fahrenheit temperatures.

However, these hardy fish can quickly adapt to other temperatures, but it’s best to aim for the range mentioned above. With too cool temperatures, they’re more susceptible to disease or illness.


Zebrafish should be kept in water with a pH between 6.8 and 7.5. It’s crucial to check daily to monitor and adjust as necessary.


It’d be best if you only kept Zebra Danios in freshwater (0 ppt). Most systems for Danios use dechlorinated tap water or deionized water.

Tank Setup

Luckily, you don’t need much to keep a thriving Zebra Danio tank. Your primary focus should be on choosing the best filter and keeping up with the tank’s hygiene.

Not keeping up with a cleaning routine puts your fish at risk for illness, disease and even premature death.


Zebra Danios usually swim in bodies of water with a sandy or silty substrate. However, you don’t need to mimic what they’re used to in the wild. While they may venture to the bottom here and there, they don’t tend to glide along and get injured.

You can use standard aquarium gravel if you like, and it shouldn’t be an issue. Whether you go for sand or gravel, opt for a dark mix to allow their colors to pop.


Zebrafish enjoy having plenty of decorations to explore around and hide behind. Their personal favorite is bogwood, though they aren’t too particular with the type of decor you choose.

The vital thing to remember is not to keep the tank too open. If they don’t have areas to explore, they may become more aggressive.

You can use just about any type of decor you prefer. However, dark color shades will make them stand out, much like the darker substrate. Make sure that you leave a good amount of space in the middle to give them room to swim.

Ideas for decor:

  • Driftwood
  • Small fake houses
  • Caves
  • Sunken ships
  • Statues
  • Bubble chests or airstones (some Zebrafish like to play in the bubbles)

No matter the decor you choose, be sure to check for sharp edges before adding to your tank. Clean anything you add to the aquarium thoroughly to prevent spreading bacteria.


Ideally, you should provide your Zebra Danio fish with live aquatic plants. Zebrafish appreciate plants since they come from densely vegetated environments.

You can opt for live aquatic plants or artificial greenery, though consider adding at least one living plant.

When choosing placement for your plant, make sure you don’t take up too much space. The Danio will enjoy exploring the edges of the tank and actively swimming throughout the middle of their enclosure.

Some plants that’ll do well in the Zebrafish’s tank include:

  • Amazon Sword
  • Anacharis
  • Hornwort
  • Java Moss
  • Java Fern

If you do opt for fake plants, be sure not to add floating betta leaves of other plastic plants that float. Like with decor, ensure that plants don’t have any sharp edges that may cut their skin.

Even though your fish will spend most of their time in the top areas of the aquarium, they may swim down to explore the bottom plants.


Lighting isn’t the main issue for Zebrafish, so most lighting situations will do. Certain varieties, like GloFish Danios, will stand out more with LED lighting, however.

When you use lighting, try to only keep it on during the day. Like us, they do most of their sleeping during the night and then actively swim when there is any light.

It’s easier for your fish to be on a regular sleep schedule when the lighting is consistent.

Zebra Danio in Front of Plants


Good filtration should be one of your top concerns for your Zebra Danio tank. A proper filter will help to keep the water clean, maintain oxygen levels and give your fish a gentle flow to mimic their natural environment.

Although some Zebra Danio live in stagnant ponds, they enjoy gentle currents. Your fish may even play in the water flowing from the filter or swim through the bubbles.


While adding a heater can be beneficial, it’s unnecessary for most Zebrafish enclosures. You likely don’t need one as long as your tank is in an area with somewhat consistent temperatures.

However, if you’re someone who keeps your home warm during the day and cold at night, a heater may be necessary.


As omnivores, Zebrafish aren’t picky when it comes to what you feed them. In the wild, they’ll feed on just about anything they can get their mouths on, including insects, algae, worms, and fish scales.

When in captivity, they’ll also need a good blend of foods. You can make their meals easier by offering pellets or flakes twice per day.

You’ll only need to give them what they can eat in a couple of minutes. Overfeeding can lead to bloat or cause murky water that’ll need changing.

Periodically, offer your fish some fresh vegetables such as:

  • Peas (remove the skin)
  • Small pieces of raw squash or cucumber
  • Lettuce leaves (no stem)
  • Baby lima bean pods

Before offering your Danio any vegetables, be sure to wash them thoroughly. Once they finish their snack, remove any uneaten bits you can.

Although they don’t spend a lot of time at the bottom of the tank, they’ll snack on algae wafers if added.

You may also add in meat sources periodically as well. Their favorites include:

  • Frozen bloodworms
  • Frozen Brine shrimp
  • Frozen unhatched crawfish
  • Live worms
  • Live Crickets

It’s unnecessary to feed fresh vegetables or protein every day. Just offer these options as treats every other week or so.


When it comes to breeding aquarium fish, you can’t get much easier fish to breed than Zebra Danios. Unlike most other freshwater fish, once they find a mate, they stay together for life.

They often won’t mate with other fish even once their partner dies.

Zebra Danios breed during the monsoon season, which is June-September in Asia. Females are at optimal breeding age when they are between 3-18 months old.

To get started, add at least six Zebrafish to a tank and let them choose their mates. The males will chase the female fish around and try to nudge her to a spawning site.

Once the female is pregnant, her belly will start to round out.

You may wait until you notice a pregnant fish or watch the shoal to see which fish seem to be a pair. However, it’s easiest to let them do their thing before separating.

Male Zebrafish will fertilize the embryos, which develop externally on the female. Because it’s easy for scientists to view the external embryos, Zebrafish make great subjects for research.

Create a breeding tank with only about half a foot of water. Add plenty of plants and decor to your tank.

Aquarium gravel works best as a substrate because it allows the eggs to land within the chunks of rock. They can lay up to 200 eggs per week.

The tank should be around 78 degrees to give your fish the cue to mate.

After she lays the eggs, remove the adult fish from the enclosure as they will also attempt to eat their young.

The fry should hatch within a couple of days and will be challenging to see. Make sure to be careful when cleaning the tank or changing out water to ensure they don’t get lost.

You can feed them fry food from a pet store. A powdered egg is another easy option for them to eat and will help the young Zebrafish grow.

Zebra Fish, brachydanio rerio

Common Diseases

When you keep up with tank hygiene, you shouldn’t have to worry much about diseases. The main issue for Zebra Danio is ich, which they may get if living in poor water quality.

Ich causes white spots on a fish’s skin and is contagious.

Additionally, bad water quality or a poorly set up tank may cause stress for your fish. When Zebrafish are stressed, they’re more susceptible to getting sick.

Signs of stress include:

  • Loss of appetite
  • Strange swimming patterns
  • Hiding more than usual
  • Loss of pigment in their color
  • Rapidly moving gills
  • Acting lethargic

You can also accidentally infect freshwater fish when adding new members or items to their enclosure.

Before adding anything to the tank, like substrate, decor or plants, make sure you thoroughly clean it to prevent any bacteria from sneaking in.

Luckily, Zebrafish are hardy and resilient. However, they aren’t entirely safe from getting ill, so it’s essential to know the signs so you can treat them right away.

Because Zebra Danios are community fish, one sick fish can contaminate everyone in the tank.

While Zebrafish can get any disease that other freshwater fish suffer from, such as bloat, ich or hole-in-the-head illness, they are also more prone to Mycobacteriosis and Nematode infection.


Non-motile bacteria is the cause of this disease and can cause varying symptoms in Zebrafish, including:

  • Inflammation
  • Skin or scale loss
  • Skin ulcers
  • Weight loss
  • Dropsy-like appearance

Unfortunately, this disease is difficult to treat as there is no effective cure. To ensure it doesn’t spread, remove any infected Danios as soon as possible.

You’ll also need to clean the water after quarantining the infected fish.

Nematode Infection

Nematode infection is another ailment that commonly affects Zebrafish. The first sign of this infection in your fish is a darker skin color.

Infected fish will also be more lethargic, causing them to lose their appetite and drop weight.

It is vital to ensure that they live in a clean enclosure and a proper tank set up to prevent your Zebra Danio from getting a nematode infection.

Look for signs of stress mentioned above and make any changes necessary if you notice that something is off.

Potential Tank Mates

Zebrafish need plenty of other fish to swim around with. Any less than five fish in their community can cause stress and even make them more aggressive.

These small fish make them great tank mates for plenty of fish, though they may nip fish that have longer fins.

For example, bettas, guppies and angelfish have flowy fins that may make them a target.

The best tankmates include:

  • Loaches
  • Small gouramis
  • Corydoras catfish
  • Swordtails
  • Barbs
  • Tetras

You may also house them with snails or small aquatic amphibians.

Don’t confuse tankmates for the minimum requirement of total fish, however. Even if you have five other fish species, it’s best to have a minimum of five Zebrafish as well.

Although they enjoy playing with other types of fish, they thrive in schools. Even though Zebra Danios are hierarchical, they don’t act aggressively toward one another.

The best tank mates will be those that have a similar temperament to Zebrafish. New members should be non-aggressive but fast-paced.

Mellow species may get stressed with all the activity in the enclosure, so it’s best to avoid mixing species with different temperaments.

If it seems like your Zebrafish are acting aggressively with their tankmates, add in some more decor or plants to put barriers between the animals.