Emerald Dwarf Danio (Danio erythromicron) Fish Species Profile

The Emerald Dwarf Danio are sociable, peaceful little fish appreciating company of its own. Due to the small size, any tank mates would have to be carefully considered as they can be frightened or outcompeted for food by larger or more boisterous tankmates.

However, the presence of similarly-sized, surface-dwelling species as well as plenty of plants to hide in, and an open swimming space seems to help reduce its insecurity.

It's not unusual to see nipped fins within a group though this behaviour does not usually extend to tankmates. Buy as many as you can, ideally ten or more, because when kept in bigger groups, the aggressiveness is spread between individuals plus the fish are more fearless, more often seen, and present better colouration.

The Emerald Dwarf Danio has a pale copper head, a pinkish-orange body with up to 15 iridescent blueish-green bars down the flanks and a single black spot, rimmed in copper, at the base of their caudal fin.

These fish have relatively high bodies giving them a stocky appearance, and their vivid fins set off the emerald green look and provide the fish with a gleaming look in the aquarium.

Scientific NameDanio erythromicron
Other NamesEmerald Dwarf Rasbora, Thick Band Purple Zebra Danio, Cross-banded Dwarf Rasbora
OriginsSoutheast Asia
Aquarium LevelBottom - Middle
DifficultyBeginner - Intermediate
Best kept asGroups 10+
Lifespan3 - 5 years
Maximum Sizeup to 4 cm
Water Conditions
Water TypeFreshwater
Temperature69 - 77 ℉ (20.6 - 25 ℃)
PH7.2 - 8.2
KH2 - 10
TDS150 - 300

Origins of the Emerald Dwarf Danio

The Emerald Dwarf Danio is indigenous to a mountain lake called Lake Inle and surrounding watersheds located in the western Shan State of Myanmar Burma in Southeast Asia.

Here the inhabit neutral to slightly alkaline water that is clear and shallow with a very rich, loamy substrate. These areas contain dense vegetation and submerged tree roots.


Emerald Dwarf Danios will gratefully accept live, frozen or freeze-dried foods such as brine shrimp, mosquito larvae, daphnia, microworms or blood worms.

They will also gladly accept micropellets, flake foods and algae wafers providing they can fit into their small mouths.

All of these foods will not only result in the best colouration but encourage the fish to come into spawning.

Sexing the Emerald Dwarf Danio

It is relatively straightforward to determine the difference in sexes. The males are more intensely coloured and are slightly smaller than females, and they also have a reddish-orange hint on their fins whereas the female's fins are transparent and colourless and their abdomens are more rounded than that of the males.

Breeding the Emerald Dwarf Danio

Emerald Dwarf Danios will breed smoothly and continuously in an aquarium with the correct water parameters.

Females will lay several eggs daily until spawning has completed, but because they seem to enjoy consuming their eggs and fry, it is advisable to have a separate breeding tank. The tank should have several breeding mops or masses of Java Moss so the females can deposit her eggs.

Separate the males from the females and feed them a particular diet of live foods for a week or two before spawning. The fish should be about an inch long and have good colouration when adequately conditioned. When the females have fattened up, add them to the breeding tank and towards evening before the lights turn off, add the males to the tank.

Usually, spawning will begin the following morning and continue for several days. Check the spawning mops or Java Moss daily for eggs and if you notice any take them out and place them into a grow-out tank.

After a week or so, spawning should be completed, and you can relocate your fish back to their original tank.

The grow-out tank should have an adequate air stone in the tank for water oxygenation but no filter for the first couple of weeks. After that, you can use a sponge filter.

The transparent eggs will hatch about 72 hours later if the temperature is quite warm at which time you can see the tiny fry lying on the bottom of the tank.

It would be best if you do not feed the fry until they are free-swimming Which usually takes another a week or so. You can then feed them with infusoria, cyclops, paramecium or liquid fry food daily until they start to develop. After this, you can provide them with commercial flake food, granules or baby brine shrimp.

Small daily water changes with water from the main aquarium should be carried out to maintain good water quality.

After around 6 to 8 weeks, you can slowly add the babies into the main tank. The parents will not be able to eat the fry once they are more significant than their mouths.

You maybe interested in the following profiles

Read More
Buenos Aires Tetra
Read More
Twosaddle Corydoras
Read More
Bristlenose Pleco
Read More
Giant Danio
Read More
Dwarf Chain Loach
Date Added: 9/30/2020 - Updated: 9/30/2020 9:03:03 PM