The Longfin Blue Danio is a wonderful color variation of the well-known Zebra DanioDanio rerio. It is earning popularity in its own right with its subtle but gorgeous silvery blue stippling and delicately flowing long fins. Another common name it is known by is the Longfin Blue Zebra Danio. This graceful fish was probably developed from the Leopard Danio variety of the Zebrafish as it sports the spotted patterning that popular mutation is known for.
This small beauty will reach only about 1 1/2 inches (4 cm) in length but should not be confused with another similar danio species, the Blue Danio or Kerr's Danio Danio kerri. Thought they both have a blue coloring, they are quite distinctive from each other. The Danio kerri is slightly larger at just under 2 inches (5 cm) and lacks the long fins. It also has a powdery blue color on its flanks contrasted with one or more strong pinkish gold horizontal stripes running from the tail to about half way onto the body. The stripes can be broken but overall it lacks the spotted effect of the Longfin Blue Zebra Danio.
This charming little Cyprinid fish is ideal fish for the beginner and is enjoyed by advanced aquarists as well. Like its progenitors it is very lively, hardy, and a prolific breeder. It is pretty typical of the danio group, friendly enough but definitely active and fast moving. This is a schooling fish and should be kept in a small group of at least five individuals, though ten or more makes them happier and creates a lively display. Although it may bicker and chase others of their same species, without the company these fish it will be miserable and ultimately die.
A school of these small lively fish are well suited to a smaller aquarium, 10 gallons is the minimum but 20 gallons is 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. Like all the Zebra Danio varieties they can withstand an impressive range of water temperatures and conditions, and will generally do just fine without a water heater. They can be comfortable in temperatures down to the low sixties (F), but although they are not finicky about water conditions, it's best to not keep your aquarium at any extreme.
For a very attractive effect in your aquarium try a mixed school by combining the pretty Longfin Blue Zebra Danio with some regular Zebrafish. A mix like this will provide a nice contrast of swift moving, darting color. Mixing even more varieties like the Albino Zebra Danio, Golden Zebra Danio, and Leopard Danio works equally well and creates a really exciting display. Don’t be surprised if the school spends a lot of time in the water flow of the filters or pumps as this is reminiscent of the swift moving waters found in their natural environment.
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.
The Longfin Blue Danio is a man made cultivar but its ancestry can be traced to the Zebra Danio, probably developed from the Leopard Danio mutation. Many are produced for the aquarium industry. Another common name it is known by is the Longfin Blue Zebra Danio. There are no wild populations of these color morphs.
In nature the Zebrafish show a preference to the lower reaches of streams, canals, ditches, and ponds. However their habitat does vary depending on the time of year. During the wet season they are found in large numbers in seasonal pools and rice paddies where they feed and spawn, then the adults migrate back to the faster moving waters followed by the young when they reach maturity. The substrate of the clear freshwater streams is normally rocky and shaded, while the still waters are silty with dense vegetation. 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 - There are no wild populations of this color morph.
The Longfin Blue Danio has a slender compressed body and there is a barbel at the end of each lip. These are small fish reaching lengths of only up to about 1 1/2 inches (4 cm) in the aquarium. Their progenitors, the Zebrafish, are thought to be primarily an annual species in the wild. But captive bred varieties can have a lifespan of 3 to 4 years, and some have lived up to 5 1/2 years with proper care.
This is a color morph of the Zebra Danio with a stippled silvery blue pattern. There are no other varieties of this fish but it was probably developed from the Leopard Danio as it has the spotted patterning of that Zebrafish mutation.
This fish should not be confused with the Blue Danio or Kerr's Danio Danio kerri, which is an entirely different species. The Blue Danio has powdery blue flanks with one or more strong pinkish gold horizontal stripes running from the tail to the fins, and its stripes can be broken but without the stippling of the Longfin Blue Zebra Danio. It is also a bit larger, reaching almost 2 inches (5 cm), and without the long fins.
Size of fish - inches: 1.6 inches (3.99 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 Longfin Blue Danio is a great choice for beginners and are great companions in a community aquarium. They adapt very well to different tank set ups and can handle minor tank condition fluctuations without issue. They are usually very easy to feed and get along with most tank mates. These are long finned fish so keep an eye on their long delicate fins.
Aquarium Hardiness: Very Hardy
Aquarist Experience Level: Beginner
Foods and Feeding
Since they are omnivorous, these fish will eat most any prepared or live aquarium fare, though the food does need to float at the surface. A balanced diet for them would include flake or pelleted foods, plant based food, and occasional live prey. As with all danios, these fish are quite active and have high nutrient requirements, so select a flake food that will provide for their needs. 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.
These fish are not exceptionally difficult to care for and mostly just need their water to be kept clean. At least 25 - 50% of the tank water should be replaced once a month. If the tank is densely stocked 20 - 25% should be replaced weekly or every other week. 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. Be mindful during maintenance that these fish will jump, so keep a close eye on them.
Water Changes: Monthly - It the tank is densely stocked the water changes should be done every other week.
The Longfin Blue Danio is fairly hardy and will adapt to most aquarium conditions. It is a schooling species that will spend most time in the top and middle regions, particularly if there is open water or water current. 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 to prevent jumps.
These fish are most effectively displayed in tanks with subdued lighting and a dark colored fine gravel or sand substrate. They like a well planted aquariums and a variety of plants will make them feel safe. Dense tall plantings around the sides and back are great, but these fish prefer open water in the middle of the tank for swimming.
Minimum Tank Size: 10 gal (38 L) - Though a school of danios can be kept in a smaller aquarium, they will do best in about a 20 gallon size.
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
Water Movement: Moderate
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.
The lively Longfin Blue Danio makes a good community fish. It will get along with its own kind and most other species. These danios really need to be kept in a group to feel comfortable. 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 other tank mates with a similar in temperament that can keep up with the fast paced lifestyle of this fish. Danios have been known at times to harass other fish and tankmates that need a calmer environment can become stressed. Don't keep them with fish that can eat them or fish that demand a peaceful aquarium. Also their long flowing fins are a temptation too great for any fin nipper to resist, so pick other tank mates carefully.
Temperament: Peaceful - They are good community fish with other fish that are also fast moving.
Same species - conspecifics: Yes - They are best kept in groups of 5 or more.
Peaceful fish (): Safe - These are a very lively fish so pick tankmates that will not be bothered by it.
Semi-Aggressive (): Threat
Aggressive (): Threat
Large Semi-Aggressive (): Threat
Large Aggressive, Predatory (): Threat
Slow Swimmers & Eaters (): Safe
Shrimps, Crabs, Snails: Safe - not aggressive
Sex: Sexual differences
Males are slightly thinner and smaller.
Breeding / Reproduction
Breeding the Longfin Blue Danio is very easy, and 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
Longfin Blue Danios are extremely hardy and disease is not usually a problem in a well maintained aquarium. However the finnage of this variety can be extra sensitive to fin rot and other diseases affecting that region. Fins may also be damaged during the normal activity of this fish. If large tears are noticed it may be wise to add a fin repair medication. With any additions to a tank such as new fish, plants, substrates, and decorations there is a risk of introducing disease. It's advisable to properly clean or quarantine anything that you want add to an established tank prior to introduction, so as 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.
The Longfin Blue Danio is readily available and inexpensive. They can be found in pet stores, on the internet, and through mail order.
Mike - 2015-04-20 I recently purchased five blue zebras and absolutely love their constant movements and activity level and come feeding time its enjoyable to watch their top splashing antics as they top feed.
Bob - 2012-08-05 Can they be in a 10 gallon tank with platies?
Charlie Roche - 2012-08-05 No not realy, 10g is too small just for the danios. Figure at least one gallon of usuable water for each inch your fish(s) are going to be as adults. So if you have a 50g you would need to subtract about 5 gallons for filer, substrate,plants etc so you would have approximately 45 usable gallons. 10g is just too small.
Troy - 2007-01-14 Today (13/01/07) I added the blue danio to my community tank. At first their spashing startled me, but I have since come to love to watch and listen to them. Thanks for your comments on this page which has helped me to better understand the blue danio's behaviour. They are my best buy yet...