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Danio erythromicron

(Microrasbora erythromicron)



    A tiny, striking and uncommon danio. Originally believed to be a rasbora, genetic testing placed this fish among danios in 1999, hence it’s common name, the Emerald Dwarf Rasbora.

Quick stats:

Listed tank sizes are the minimum
Size: Max length: Up to .75 in (2 cm)
Tank: School of 6: 10-15 gallons (38-57 liters) or larger.
Strata: Bottom levels
PH: pH range: 7.0 – 8.0
Hardness: medium to hard. dH range: 10 – 25.
Temperature: 68°F to 75°F (20-24°C)


Order: Cypriniformes
Suborder: Cyprinoidei
Family: Cyprinidae
Genera: Danio
Species: Danio erythromicron (Microrasbora erythromicron)




Common name:


Emerald Dwarf RasboraDistribution

    Southeast Asia: Myanmar: Lake Inle, Shan State waterhead, Kayah.

General Body Form:A taller, streamlined body with a forked tail and medium-sized, rounded fins.

Coloration:Male: Base color of body and head is pale copper. The slate blue pigment stripe running the length of the body is struck through with iridescent pale copper bars that disrupt the body’s outline. Pectoral, dorsal and anal fins have a ruddy blush proximally. At the tip of the caudal peduncle is a black oculus (eye-spot) rimmed in copper. The pink flush of the fish’s heart can be seen through the transparent operculum. Female: Very pale, translucent copper-colored body with a barely discernible pigment stripe and iridescent pale copper bars. The caudal peduncle has a faint eye-spot and the fins are barely flushed proximally. Her heart shows less intensely through her operculum.




    • water:
      Freshwater: Soft, pH neutral, crystal clear water is suggested for health and enhancing coloration. Filtration should be excellent and gentle, as a sponge filter would provide.
    • Diet:
      Omnivorus: Enjoys live and frozen artemia, bloodworms, cyclops, daphnia, grindal worms, spirulina, tubifex worms and tiny pelleted foods.
    • Tank/Decor:
      Densely planted with dark sand, fluorite or gravel substrate replicates the habitat at Lake Inle as well as providing camouflage and cover, calming the fish. Floating plants, driftwood, branches and small stones complete the environment.
    • Communities:
      Peaceful: A timid, energetic and social tankmate excellent for aquaria with similarly-sized fish such as danios, devarios, rasboras and smaller barbs. It’s colors are brightest and it’s most sociable in a shoal of at least 6-8. Keep a ratio of 1 male to 3 females. Larger groups of 15-20 fish help diffuse sparring among males during small territorial disputes.

Biotope:Usually inhabits Lake margins where live and dead vegetation produce thick mats and dense islands of vegetation.


Moderate to Difficult. Egg-scatter. Sexual dimorphism: Males are more intensely colored and slightly smaller than females. Females are larger and fuller-bodied, especially when they are gravid with fry. Condition prospective mates with a diet rich in live and frozen foods for a few days. Because adults predate fry, a spawning tank with a sponge filter, multiple plants, spawning mops, and baby grass is recommended. Typically in the morning hours, males and females will release eggs and sperm into the water column and eggs are fertilized as they descend. Eggs adhere to the baby grass and spawning mops and fry emerge after roughly 72 hours. They are free-swimming within 3-4 days. Feed the fry very tiny food such as paramecium, fry food or crushed flakes. Graduate to artemia nauplii, cyclops and microworms when fry are large enough to accept them


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