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Danio roseus



    A tiny fish perfect for nano tanks. D. roseus males put on a show during spawning season, brightening up from being opalescent blue with rosy abdomens, to vibrant shades of purple to attract their mates. Peaceful tankmates, these strong, hypnotic swimmers are an energetic addition to any aquarium.

Quick stats:

Listed tank sizes are the minimum
Size: Adult Male/unsexed: 1.46 in (3.7 cm)
Tank: School of 6: 20 gallons (75.7 liters) or larger
Strata: Top (pelagic)
pH: pH range: 6.0 – 7.5
Hardness: Soft to medium. dH range: 2 – 15.
Temperature: 68°F to 77°F (20-25°C)


Order: Cypriniformes
Suborder: Cyprinoidei
Family: Cyprinidae
Genera: Danio
Species: Danio roseus


Common name:


Purple Passion Danio

    , Rose Danio


    Asia: Mekong basin in Thailand, Laos and Myanmar in relatively cold springs, small creeks and the Mekong main river.

General Body Form:A moderately rounded, laterally-elongated fusiform shape. Fins are moderate-length and rounded, with a homocercal caudal fin. Small terminal mouth with two pair of long barbels. (D. roseus has a shallower, more slender body and shorter rostral barbels than the next most similar species, D. albolineatus (Pearl Danios.)

Coloration:A beautiful rosy-peach coloration underlies pale blue stripes running the length of females and intense purple-blue coloration along the flanks of males. Males further have deeply rose-colored abdomens, dorsum, anal and pelvic fins as well as a flush of the color on the caudal peduncle. Color differences between the sexes are most noticeable during spawning time.


Diet:Omnivorous: Feeding primarily of insects and larvae in nature, in the aquarium, D. roseus eagerly accepts live and frozen bloodworm, brine shrimp and daphnia as well as quality small pellet and flake variety diets. For best coloration, live and frozen proteins should be offered at least part of the time.



    1. Danios enjoy the longest tank you can afford them. A small stream or riverine tank can be established with a substrate of gravel, small stones or water-worn small, variably-sized boulders. Driftwood, branches and plants serve multiple purposes—décor, cover and, in the case of the plants, increased biological filtration. Anubias and water ferns are recommended both for their ability to be secured to driftwood and rocks as well as their hardiness in a tank with a moderately strong current. For best success, low lighting (of 45 – 60 watts) is recommended. This might be accomplished by keeping the tank by a window with moderate morning sunlight. With higher light and the addition of CO2, both plants grow quickly and lushly, so ensure your water column contains the sufficient nutrients. Both darker substrate and plants have the effect of brightening the coloration of the fish. To replicate this variety of conditions, begin with strong current from your filter output (which can be increased by adding a small powerhead or circulation pump, basing the amount of circulation by the constitution of other fish that may be in the tank.) Ensure stretches of calmer water for resting, simulating marginal areas in their natural habitats. Danio are strong swimmers and are prone to jumping, so be sure to provide a tight-fitting lid for your aquarium. This very peaceful little fish is stunning in a species-only tank and are perfect tank-mates for a non-aggressive community tank. In groups of 8 – 10 or greater, males demonstrate brighter colors as they compete with rivals for the attention of females. They’re best kept in a ratio of 1 male to 2 females. Anabantids, barbs, other small danios, rasbora, catfish, livebearers, loaches, rainbowfish and tetras would all be peaceable companions. One endearing trait of danios is their ability to be dither fish, calming others and assuring them freedom from predation with the regular, whirling motion of their swimming patterns, coaxing more nervous fish out of hiding.



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Biotope:Freshwater: In nature, D. roseus is accustomed to cool running water, springs associated with waterfalls, small creeks as well as the Mekong River.


Oviparous: Egg-scattering free-spawners: Easy. Males are both sexually dimorphic and mildly dichroic, having brighter colors and rounder bodies than females. The greatest challenge to overcome is Giant danios are voracious egg-eaters. A breeding tank– at least 10 – 20 gallons (37.9 – 75.7 liters) –with marbles as substrate allow the eggs to fall between the marbles and safely out of reach of their parents mouths. Additionally, your tank should have heated, mature water, a sponge filter and an air stone for oxygenation and circulation (the addition of baby grass, java moss or spawning mops is optional as the safest place for the eggs to fall is between the marbles.) At least a week prior to spawning, condition the parents on a diet rich in protein such as bloodworms, brine shrimp or tubifex worms which will help build roe in the female. When the female(s) to be spawned appear gravid (their abdomens will be distended with eggs and a small dark spot will appear just before the fish’s urogenital opening,) one or two pair should be placed into the breeding tank toward evening (as spawning will occur around dawn.) When ready, the female releases close to 300 eggs, with the male following, fertilizing the eggs as he swims along. Giant danios provide no aftercare for the eggs, so it’s best to remove the adults within 24 – 48 hours of spawning. Incubation of the eggs generally takes 24 -36 hours, with the fry being free-swimming a few days later. Initially offer the fry green algae, small crustaceans, paramecium and protozoans common in aufwuch cultures, segueing to Artemia naupaii and crushed flake food in a week or so once the fry are large enough to accept the larger foods.

References:Brachydanio rosea
Danio roseus
Nana (Anubias barteri ‘Nana’)
Java Fern (Microsorum pteropus)

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