The zebra danio, also known as the striped danio or zebrafish, is a small freshwater fish.
Zebra danios are one of the most popular freshwater species found within the aquarium hobby and have been selectively bred and genetically modified to change their appearance.
Danios are a very hardy and social species making them the perfect fish for any beginner and will add a spark to any community aquarium.
They can be found in lots of different color variations and as a shoaling species, they add diversity and animation to your tank.
TABLE OF CONTENTS
Zebra Danio Facts & Overview
|Color Form:||Natural silver and blue striped, golden, albino & glo morphs|
|Minimum Tank Size:||10 gallons|
|Tank Set-Up:||Freshwater with plenty of plants|
|Compatibility:||Very social and community species|
Zebra danios (Danio rerio) are a freshwater fish species of the Cyprinidae family. They are a widely distributed species ranging from India up to Nepal.
This species is one of the most common aquarium fish for a number of different reasons.
Zebra danios are peaceful, social, and relatively easy to care for as they are very hardy.
This species can be purchased in most local fish stores for around $2 per fish. They have a maximum lifespan of around five and a half years.
As well as being a popular aquarium species, they are also used as test subjects for various scientific research purposes. These fish are a highly researched species that are studied for numerous purposes. They are frequently studied as a model vertebrate species.
Surprisingly, humans and zebra danios share 70% of their genes with one another.
Zebra danios are a relatively social species and exhibit shoaling behavior.
These shoals can have a hierarchical system of dominance established through playful non-aggressive behavior.
While they are social and peaceful fish, they can be seen chasing each other around the tank. They can display aggressive behavior towards slow-moving, long-finned fish species and they may frequently be seen biting at their fins.
As they are community fish, they don’t do well on their own, as this can cause them to be stressed which can lead to illnesses. It can also lead to them becoming less active and choosing to spend their time hidden away.
Keeping them in large shoals can have a drastic effect on their behavior, and can cause them to become hyperactive in the aquarium.
They can be seen occupying all levels of the aquarium but predominantly the middle to upper layers of the tank.
In the wild, these fish are small and grow up to two inches in length. They have a silvery/gold coloration with fix blue stripes which extend from the head to the caudal fin.
With this species, there is some form of sexual dimorphism with the background coloration of males being more golden than the silvery-white coloration of females.
Male fish also tend to be slimmer than the fuller bodied and rounder females.
Another variation of this species is the longfin zebra danio. As its name suggests, it has been selectively bred to have longer fins than its wild counterparts.
They can be found in many different colors within the aquarium industry.
A naturally occurring color morph of this species is the albino form. This is rare in the wild but quite common in the aquarium industry. In the wild, individuals bearing this coloration would quickly become prey.
Other than the natural color variation, you can also find golden morph zebra danio. The blue stripes of the natural variation have been completely bred out leaving it with a yellowish gold body with silvery white stripes.
Genetic modification has led to an increase in the color variations of this species. By transplanting the genes of jellyfish, scientists have created zebra danios which glow in the dark under black light and come in fluorescent red, blue, green, orange-yellow, and purple forms.
These genetically modified variants would not survive in the wild due to increased predation.
Zebra Danio Size
This species can grow up to two inches in length.
However, zebra danios can grow larger than this when kept in ponds instead of indoor aquariums.
This is most likely due to the larger amount of space and natural food sources which a pond provides.
Habitat and Tank Conditions
The zebra danio is found at tropical and subtropical temperatures from India and Bangladesh to Bhutan.
During the summer months, temperatures can range from 77-82°F, but this will drop during the winter months.
Zebra danios are found in a range of different habitats, from slow-flowing rivers and streams during the dry season to seasonally flooded pools/ponds and rice paddies during the monsoon season.
Their habitats consist of silty-bottomed rice paddies full of lush green vegetation. They can also occupy verged areas with rocky substrates and overhanging branched cover.
As with all countries in the northern hemisphere, during the winter months, light levels are decreased. Gradual increases can be seen from the spring and into the summer months where they can receive 12 hours or more of daylight.
These conditions are simple to replicate in your aquarium.
Firstly, fine, soft sediment such as treated sand should be used.
The substrate should always be thoroughly washed before being added to the aquarium to avoid cloudy water, which will take a few days to settle.
Once the substrate has been laid, water can be added to the aquarium slowly to avoid stirring up the substrate. The temperature of the water can range from 64-77°F with a pH of 6.0-8.0.
With the water and the substrate now in place, aquascaping your aquarium can now begin.
These plants are also useful hiding places, in addition to making your aquarium look great and natural. This also increases habitat complexity which has been proven to reduce aggressive behavior.
Depending on the size of the aquarium, you can also add pieces of bogwood to represent the underwater tree roots that would be found along the river and stream verges of their natural habitats.
Large rounded pebbles can also be placed in the tank to replicate the rocky bottomed rivers.
A good filtration system should also be purchased. The type will vary depending on the size of the aquarium and the quantity of fish in the aquarium.
The aquarium can be set up to have an artificial source of light, receiving roughly 12 hours of light per day.
What Size Aquarium Do They Need?
The minimum recommended aquarium for a zebra danio is 10 gallons.
How Many Can Be Kept Per Gallon?
We recommend keeping one zebra danio per two gallons of water. This will give the fish plenty of space to shoal and swim freely throughout the aquarium.
This will also avoid overstocking.
In the wild, zebra danios can be found in waters along with other species like Indian flying barb, honey gourami, scarlet badis, and emerald pufferfish. All of these would make suitable tank mates, as would ember tetras, Bengal turquoise danios, celestial pearl danios, and Burma danios.
Aquatic invertebrates can also make good tank mates, such as snail species like zebra snails and other nerites, frogs like the African dwarf frog, and freshwater shrimp, such as the blue velvet shrimp.
You should avoid keeping them with long-finned fish such as sailfin molly fish or elephant ear guppies. Your danios will nip at the tail fins of these fish.
This fin nipping behavior can be a sign that either, the tank is too small, or, the zebra danio shoal is too small.
Avoid keeping predatory fish like catfish species such as redtail catfish.
Keeping Zebra Danios Together
Zebra danios should not be kept on their own as this can induce stress and cause them to become aggressive.
They are a social species that belong to a shoal. They should be kept in groups consisting of no less than 5 individuals.
In the wild, this species is omnivorous and will feed on mosquito larvae, small crustaceans, worms, and algae.
Within the aquarium, they can be fed a variety of foods.
The core of their diet will be a good quality flake and you can occasionally use an algae-based flake food.
You can also try to feed them fresh vegetables like zucchini, cucumber, shelled peas, and spinach. Live foods like daphnia and bloodworms can also be fed to zebra danios once a week as a treat. If live foods are unavailable most stores will sell dried or frozen options.
Fry should be fed specially developed food nourishment for egg-laying species and then as they grow, should be moved onto a follow-on baby fish food to promote healthy growth.
The quantity of food you feed your fish will vary with the number of fish being kept in your aquarium. Try to feed little pinch-sized portions often a few times a day that they can consume within three minutes.
Zebra danios are the perfect breeding fish for beginners. In the wild, breeding is induced by a change in temperature at the start of the monsoon season.
To start off the breeding process, males and females should be separated for a few weeks and a breeding tank (5-10 gallons) should be set up at a temperature of 71–80°F.
While separated, males and females should be fed high-quality live foods like daphnia and bloodworms. You should be able to see the females growing rounder (indicating the development of eggs).
After the two-week feeding period, the males and females can now be placed into the breeding tank with a ratio of two males for every female. They will usually spawn within 24 hours.
The best indication of breeding is the presence of fertile translucent eggs at the bottom of the breeding tank. Infertile eggs are white.
After spawning, males and females should be removed and placed back into their home aquarium as they will eat the eggs if not separated. Fertile eggs take around three days to hatch into fry. The fry are tiny and transparent, and during this early life, stage should be fed foods as described in the feeding section above.
Zebra danios are usually straightforward and easy to care for. Providing that husbandry requirements are being maintained to a high standard, diseases and infection outbreaks are usually avoided.
Mycobacteriosis is a common disease that zebra danios are susceptible to. This disease is caused by several different types of non-motile bacteria found in water.
The diagnosis of mycobacteriosis can be done by assessing the fish’s health signals. These include ulceration, inflammation of the skin, anorexia, lethargy, and even fin loss. Outbreaks can be worsened by poor water quality, fish stress, and other types of failures in animal husbandry.
Treating mycobacteriosis with antimicrobial treatments is usually ineffective. The priority should be to remove the fish from your aquarium as soon as possible and complete water changes to improve water quality.
If infections spread throughout the tank, you should go about the complete eradication of current stock however unfortunate it may be, and proceed with the thorough disinfection of the tank before the addition of new fish.
Also, be mindful that mycobacteriosis is a zoonotic disease that can also infect humans. Do not work with the aquarium if you have open wounds on your hands and arms. If maintenance is essential, then specialized arm-length aquarium gloves may be purchased.
Another type of infection that zebra danios are affected by is intestinal nematodes. They are caused by a species of nematode worm-like Pseudocapillaria tomentosa.
Infected fish are darker in coloration and appear to be lethargic. Weight loss is also commonly associated with intestinal nematode infections.
To avoid the spread of infection to other fish, the infected specimen should be removed from the aquarium and placed into a separate quarantine tank, and be treated.
Are Zebra Danios Suitable For Your Aquarium?
A shoal of zebra danios would make a great addition to the aquariums of both beginners and experienced fish keepers.
Their vibrant colors and social hyper activeness would allow you to make your aquarium stand out whilst also adding character.
The addition of these fish to your aquarium is sure to put a smile on anyone’s face, thanks to their boisterous darting behavior.
Although these hardy fish can tolerate low-quality waters, it is essential when keeping any species that you maintain a high level of husbandry to keep the aquarium healthy and free of diseases.