Zebra Danio

Zebrafish, Striped Danio, Zebra Fish

Family: Cyprinidae Picture of a school of Zebra Danios, Danio rerio, ZebrafishDanio rerioPhoto © Animal-World: Courtesy David Brough
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I have two Zebra Danios and they are lovely fish they are always chasing each other and having fun. They get on with my neon tetras, glow light tetras, my lemon... (more)  Connor

The Zebra Danio is a popular aquarium fish favored for its charm and grace, and above all for its hardiness!

The Zebra Danio Danio rerio (previously Brachydanio rerio) is a lively little schooling fish that only reaches about 2 1/4 inches (6 cm) in the aquarium. It's easy to recognize with an attractively striped black and white "zebra" patterned body. This is one of the first types of tropical fish to ever be kept in the aquarium, and it is still enormously popular. Its very pretty, inexpensive, and a great for both beginners and advanced aquarists. Other common names it is known by are Zebrafish, Striped Danio, and Zebra Fish.

There are dozens of variations of this Danio selectively bred today, and certainly a variety to suite every taste. Some of the best known include the Longfin Zebra Danio and color morphs like the Golden Zebra Danio, Albino Zebra Danio, Longfin Blue Danio, and Sandy Zebrafish. Other well known varieties are the Leopard Danio and Longfin Leopard Danio that have spots instead of stripes. There is also a variety called the Hybrid Danio for those who just can’t choose between spots and stripes, which has a combination with both. A more recently introduced variety is a Zebrafish (Danio rerio) genome known as the “Glo-fish”. This is a genetically modified little fish available in beautiful fluorescent colors of bright red, green, orange-yellow, blue, and purple.

These hardy and attractive Cyprinids are ideal for beginners. They are prolific breeders and are the easiest type of egg layers to breed. As a schooling fish they should be kept in a small group of at least three individuals, though a schools of 5 or more is best. And being small, a school is suited to a smaller aquarium with 20 gallons being optimal. They can be housed with most any community fish, just make sure that the danio will not be eaten and that the other fish aren’t startled by swift movement.

Zebrafish are very durable and can withstand an impressive range of water temperature and conditions. They will generally do just fine without a water heater as they are comfortable at temperatures down to the low sixties (F). But even though they are not finicky about water conditions, it's best to not keep your aquarium at any extreme. Don’t be surprised if the school spends a lot of time in the water flow of the filters or pumps as a swift moving environment is what they are accustomed to in nature.

Care needs to be taken that neither specimens of this fish nor fertilized eggs be released into the environment. They are a tropical fish, and can't survive in areas of extreme weather conditions. They have been used for mosquito control and has invasively populated some environments.

For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care

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Geographic Distribution
Danio rerio
Data provided by FishBase.org
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Cypriniformes
  • Family: Cyprinidae
  • Genus: Danio
  • Species: rerio
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Zebra Danio - Quick Aquarium Care
  • Size of fish - inches: 2.4 inches (5.99 cm)
  • Minimum Tank Size: 10 gal (38 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Very Hardy
  • Temperature: 64.0 to 75.0° F (17.8 to 23.9° C)
  • Aquarist Experience Level: Beginner
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Habitat: Distribution / Background

The Zebra Danio Danio rerio (previously Brachydanio rerio) was described by Hamilton in 1822. They are found in Asia from Pakistan to India and as far as Myanmar. They occur in the Kosi River in Uttar Pradesh, northern India and in smaller numbers in Nepal, Bhutan and Bangladesh. This species is listed on the IUCN Red List as Least Concern (LC) as they are widespread throughout their range with no major identified threats. Other common names this species is known by include Zebrafish, Striped Danio, and Zebra Fish.

There are dozens of variations of this Danio, with the Albino Zebra Danio being a naturally occuring color morph. Many varieties and color morphs including the Albino, Longfin, Golden, Sandy, and Leapard Zebra Danios, are bred in captivity today. A more recently introduced variety is a Zebrafish (Danio rerio) genome known as the “Glo-fish”. This is a genetically modified little fish developed by scientists. By adding a natural fluorescent gene to the fish, which will absorb light and then re-emit it, the hope is to be able to detect contaminates in waterways. Though Glofish are perhaps the most controversial little fish in the hobby, at present there are no known adverse effects to the fish or to the environment. They became commercially available in the United States in late 2003, and are offered in beautiful fluorescent colors of bright red, green, orange-yellow, blue, and purple.

This fish inhabit the lower reaches of streams, canals, ditches, and ponds. Their habitat varies greatly depending on the time of year. Adults are found in large numbers in seasonal pools and rice paddies during the wet season where they spawn and feed. These are still waters with a substrate that is silty and heavily vegetated. The adults then return to the faster moving waters of rivers and streams for the dry season, where the substrate is normally rocky and shaded. The young will stay in the still waters until maturity then they too migrate to the rivers. In the wild these fish are considered micropredators and feed on worms, small aquatic crustaceans, insects and insect larvae.

  • Scientific Name: Danio rerio
  • Social Grouping: Groups
  • IUCN Red List: LC - Least Concern

Description

The Zebra Danio has a slender compressed body. There is a barbel at the end of each lip. These are small fish reaching lengths of only up to about 2 1/4 inches (7 cm) in the aquarium, though they can get slightly larger in a pond. They are thought to be primarily an annual species in the wild, but in captivity can have a lifespan of 3 to 4 years, though some have lived up to 5 1/2 years with proper care.

The body of this species has a very pale yellow to white background marked with five steel blue horizontal stripes that fade into the fins and extend onto the tail fin.

Some varieties and color morphs of this fish include:

  • Long finned Zebra Danio
    This is merely the Zebra Danio selectively bred to have more extended fins. It has nearly exceeded the traditional variety in popularity.
  • Leopard Danio & Longfin Leopard Danio
    Although sometimes separated as a different species, the Leopard Danio is actually a captive bred color morph first developed by a Czech scientist. Rather than having the stripes, this sides of this fish are adorned with steel blue spots. They will readily school with regular Zebra Danios, and can even breed together. The long fin variety has been bred to have an extended tail and fins.
  • Hybrid Danio
    The Hybrid Danio is another bred color morph for those of us who just can’t choose between spots and stripes. Its side is spotted about halfway down the body, at which point the spots condense in to stripes. Hybrid danios are fairly new to the hobby. They also can breed with either the Leopard or Zebra Danio but offspring won’t stay true to the parent’s coloration.
  • Golden Zebra Danio
    This is a gold color morph of the Zebra Danio, which has had the blue stripes bred out. This fish can sometimes be confused with the Pearl Danio Danio albolineatus, which is an entirely different species.
  • Albino Zebra Danio
    This color morph is a naturally occurring phenomenon, It has an absence of pigments on the fish’s body surface. Also not to be confused with the Pearl Danio.
  • “Glo-fish”
    This little fish is a more recently introduced Zebrafish (Danio rerio) genome. It has been genetically modified to sport fluorescent red, green, orange-yellow, blue and purple colorations. They also glow in the dark or under a black light. Their care does not vary from the natural Zebra Danio.
    • Size of fish - inches: 2.4 inches (5.99 cm)
    • Lifespan: 4 years - They have an average lifespan of about 3 1/2 years, though some have lived up to 5 1/2 years with proper care.

    Fish Keeping Difficulty

    The Zebra Danio is a great choice for beginners, and are great companions in a community aquarium. These fish will eat just about anything that is offered, as long as it floats at the surface where they can readily consume it. They tolerate water condition changes with out too many issues and can even be kept without a heater.

    • Aquarium Hardiness: Very Hardy
    • Aquarist Experience Level: Beginner

    Foods and Feeding

    These fish are omnivorous feeding mostly on a variety of worms, small crustaceans, and insect larvae in the wild. In the aquarium they will eat most any prepared or live aquarium food, though it does need to float at the surface.. They enjoy chasing after tubifex worms, whether living or freeze dried. These fish will do best when offered food several times a day, but offer what they can eat in 3 minutes or less at each feeding. If you feed only once per day, provide what they can eat in about 5 minutes.

    • Diet Type: Omnivore
    • Flake Food: Yes
    • Tablet Pellet: Yes
    • Live foods (fishes, shrimps, worms): Some of Diet
    • Vegetable Food: Some of Diet
    • Meaty Food: Some of Diet
    • Feeding Frequency: Several feedings per day - Offer only what they can consume in 3 minutes or less with multiple feedings per day.

    Aquarium Care

    These fish are easy to care for, mostly just needing the water to be kept clean. Aquariums are closed systems and regardless of size all need some maintenance. Over time decomposing organic matter, nitrates, and phosphate build up and the water hardness increases due to evaporation. Replace 25 - 50% of the tank water at least once a month. If the tank is densely stocked 20 - 25% should be replaced weekly or every other week.

    • Water Changes: Monthly - It the tank is densely stocked the water changes should be done every other week.

    Aquarium Setup

    The Zebra Danio is a schooling species that will spend most time in the top and middle regions, particularly if there is open water or water current. This fish as fairly hardy and will adapt to most aquarium conditions. The waters they inhabit in the wild are acidic, but the stock now available in the hobby is many generations past this. Though a school of danios can be kept in a smaller aquarium, they will do best in about a 20 gallon size. Provide good filtration and the tank should be covered as these fish may jump.

    These fish are most effectively displayed in tanks which simulate their natural habitat to bring out their colors. Use a dark colored fine gravel or sand substrate and provide a variety of plants will make them feel safe. Some good selections include Water Wisteria, Hornwort, and Java Moss. As with most of the Cyprinid fish they are most at home in well planted aquariums, but as these fish are extremely active swimmers they also need some open areas for swimming.

    • Minimum Tank Size: 10 gal (38 L)
    • Suitable for Nano Tank: Yes
    • Substrate Type: Any
    • Lighting Needs: Moderate - normal lighting
    • Temperature: 64.0 to 75.0° F (17.8 to 23.9° C)
    • Range ph: 6.0-8.0
    • Hardness Range: 2 - 20 dGH
    • Brackish: No
    • Water Movement: Weak
    • Water Region: All - They will spend most of the time in the top and middle regions of the aquarium, particularly if there is open water or some current.

    Social Behaviors

    The lively Zebra Danio makes a good community fish. It will get along with its own kind and most other species. They are best kept in a school of 5 or more of their own kind. Groups of this fish can be hierarchal and a pecking order may emerge in the school, but nothing will come of it. Select tank mates that are similar in temperament. You want tankmates that can keep up with the fast paced lifestyle of this Danio. Mellower fish that need a less hectic environment can become stressed.

    • Temperament: Peaceful - They are good community fish with other tankmates that are also fast moving fish.
    • Compatible with:
      • Same species - conspecifics: Yes - They are best kept in groups of 5 or more.
      • Peaceful fish (): Safe - Tankmates need to be able to tolerate the lively nature of this species.
      • Semi-Aggressive (): Monitor
      • Aggressive (): Threat
      • Large Semi-Aggressive (): Threat
      • Large Aggressive, Predatory (): Threat
      • Slow Swimmers & Eaters (): Monitor - Large groups of Zebra Danios may make these fish nervous because of their activity level.
      • Shrimps, Crabs, Snails: Safe - not aggressive
      • Plants: Safe

    Sex: Sexual differences

    The females are generally more colorful, and the males are more streamlined and slim in body shape.

    Breeding / Reproduction

    The Zebra Danios are very easy to breed, and it may even occur on accident. Two fish will form a breeding pair which they often keep for life. If you wish to retain the young, the breeding tank should be empty except for a two inch layer of large glass marbles, 1/2 to 1 inch in diameter. Add the female to the tank and let her settle for about a day before adding the male. When they are both in the tank, adding a few cups of cold water will cause the courtship to begin.

    If conditions are favorable, the female will release her eggs in open water and the male will fertilize. The eggs will then sink to the bottom and fall through the marbles, out of their parents reach. The fry will emerge from the marbles after about 7 days. At that time or before, parents should either be removed or kept constantly well fed. See the description of breeding techniques in: Breeding Freshwater Fish: Barbs. Also see Fish Food for Fry for information about types of foods for raising the young.

    • Ease of Breeding: Easy

    Fish Diseases

    Zebra Danios are extremely hardy so disease is not usually a problem in a well maintained aquarium. They are primarily susceptible to Ich if good water quality is not provided. Anything you add to your tank can also bring disease. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance.

    These fish are very resilient but knowing the signs of illness, and catching and treating them early makes a huge difference. An outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. The best way to proactively prevent disease is to give your fish the proper environment and a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. A stressed fish will is more likely to acquire disease. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.

    Availability

    The Zebra Danio is readily available in stores and online and is inexpensive.

    References

    Author: Barbara Roth, Clarice Brough CFS
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    Lastest Animal Stories on Zebra Danio


    Connor - 2014-10-15
    I have two Zebra Danios and they are lovely fish they are always chasing each other and having fun. They get on with my neon tetras, glow light tetras, my lemon tetras and my cherry barbs, my guppies, my honey gourami and my horse face loach. They are lovely fish to have so I recommend that you have them in a community tank.

    Reply
    Doug - 2009-03-13
    Don't know why it's not on here but zebra danios will kill neon tetras. I have had fish for 15yrs & every time I put zebras in my tank they kill my neons. It's happened 6 differnt times. Has anyone else had this problem?

    • chad - 2010-02-19
      I have 4 glofish and one zebra danio. I recently added one glow light tetra and it was very calm. I thought these fish would get along, but now two days after I buy the tetra; I come home and my glofish had killed my tetra.
    • Gord - 2010-04-21
      I have had the same experience. I have introduced neons to a community of danios and bloodfins twice, and the neons disappeared within a two or three weeks. I would advise against trying to house them together.
    • caity - 2010-05-24
      eeee really I have not got them yet but I am getting soon. Do the zebra danios eat the neon tetras I have them :(
    • lps - 2010-07-25
      I'm having that same exact problem! How do I stop it from happening?!
    • w. r - 2011-01-16
      Yes, I first started my new tank with 1 zebra danio and yesterday I bought a neon tetra soonest I put it in the tank the zebra started to chase him, I return it to the store and came with another zebra and the biggest one started to chase the small zebra, are this fish crazy or what?, I think that they might need xanax.
    • Alden Finnie - 2011-09-10
      Wow, That's weird. I have 18 neon Tetras and 6 Zebra Danios. They get along fine and it's been 8 months. The Danios only seem to harmlessly bother each other. Chasing each other in a big circle around a rock.
      Thanks though. I'll keep an eye on them.
    • carla - 2011-09-15
      Hi I would just like to say that I disagree with you, as I have danios and tetra living together, and have had no problems. They are highly compatable. Mine have been living together for over 6 months and are very happy together,
    • Anonymous - 2011-10-18
      We have had 2 danios in with our tetras for over a year and there has been no problem. The male danio chases the female and the tetra very aggressively, but that is all.
    • Kim - 2011-12-01
      I have 8 big zebra danios and I had 24 neon tetras, I now have 7 neons left! I had never thought of this before, but they are the only fish big enough to eat the neons, so it has to be them! Damn it they have decimated the neons, going to have to sell the danios I think.
    • Tanya Altice - 2012-02-20
      When I had my tank I learned that a) you have to provide schools for each fish danios like at least 5 like fish in the tank. Neons like even more than that. b) generally you buy neons very small! and and small new fish don't do well with established bigger fish. So I would say get a small 5gal tank and set it up for a school of about 8 neons and let them get bigger than what you normaly buy them. Then put them in your tank with the others and give your danios some friends to play with so they will leave the others alone. Also neons aren't very hardy. I have had several trips around and around with neons where they simply die within a week of buying them. So be prepared to spend some time building a good school of neons.
    • Alonzo T. Fells II - 2012-04-15
      I have to disagree with that. I had group of 5 zerbra danios and they never had bother the neon or the rest of mine tetras. Yea, a little bit of fish nipping but they play tag with mine rams lol
    • Maeve - 2012-05-20
      Oh, really? I didn't know that. Do danios get along with goldfish?
    • Jeremy Roche - 2012-06-26
      Zebras Danios are famous for stressing and harrassing other fish.  They are small but they are very fast swimming and in groups this can be taken as aggressive and make others stressed.  Neons are easily stressed.
    • aiden - 2012-06-26
      i just put 10 neons in my tank with my 2 zebra danios, (there were 3 but the others bullied the smallest until it died) 3 hours later the first neon is dead and they're trying hard to single off another!
    • Anonymous - 2014-06-06
      I have zebra and leopard ones they killed my goldfish 😒
    Reply
    Fish keeper - 2006-08-09
    I have 4 of the little guys and they are great fish. they will some times split up from their group and swim around in a loosely formed group. I might add 2 or 3 more to see if I can get a better schoaling behavior. great fish, fun to watch. Enjoy your danios!

    • verna - 2013-04-30
      hi, i also have 4 longfinned zebras,i was wondering if yours will feed off the bottom after feeding time,mine seem to be scavenging the bottom.my question is do i still need a bottom feeder? or would the zebras attack them?also let me know if they do school better with 5 or more,mine are quite active and go everywhere independetly.thankyou
    Reply
    Sal - 2012-06-27
    Very interesting, I just started my tank, I have 5 danios, one week into the cycle they also went crazy doing the fin nipping thing, but have stopped and only chase each other now. I have since rescued two pink danios (glofish) and introduced them to my tank with no problems. However, after the cycling period I want to add 4 cory's, 1 siamese fighter and 2 platies? My tank is 57L, any comments/advice?

    • Jeremy Roche - 2012-06-27
      Ammonia spikes will make the fish act out if tank is cycling.
    • Tate - 2012-08-22
      I have a 10gallon with otocinclus, a green Cory, and zebra danios all doing fine. I tried adding my sisters fighting fish and he kept chasing and trying to eat the danios. I wouldn't reccomend the platies, due to previous comments about the neon tetras
    Reply