Danio Erythromicron Fish Care Guide Complete

The Danio erythromicron (Emerald Dwarf Danio) is a small freshwater fish that is quite difficult to find, but still a beautiful addition to any kind of aquatic environment. Although it is considered a resistant animal, the aquarist will need to take some care when keeping this fish in an aquarium.
In the wild, the Danio Erythromicron can be found in Asia, more specifically in Inle Lake, Myanmar’s second largest lake. Inle Lake sits in a valley known as the Yawnghwe Basin, located almost 900 meters above sea level. This species of fish is usually collected on the shores of the lake where it lives among the plants, but it is quite difficult to catch. Local fishermen, for example, use special traps at night to capture them.

As much as it is a small fish, the Danio Erythromicron has an enviable beauty. As with others danios, this fish has a long and thin torpedo-shaped body. Both males and females are salmon pink in color and both also have orange faces. In addition, the species even features turquoise blue stripes that glow when under the light, creating an impressive display.

Generally speaking, if you are looking for a small, tough and ideal fish to put in a , I recommend that you search in a store in your area for these little guys. You will not regret!

Keep reading the article to check the main characteristics and needs of the species.


Name: Rasbora Esmeralda, Danio Esmeralda, Emerald Dwarf Danio, Emerald Dwarf ‘Rasbora’;

Scientific name: Danio erythromicron (Annandale, 1918);

Family: Danionidae;

Origin of Species: Asia (Inle Lake, Myanmar);

Length: Up to 3 cm;

Life expectancy: Between 3 – 5 years;

Difficulty level: Easy / Moderate;

Water Parameters

pH: Keep between 7.2 – 8.2;

water hardness: Between 2 – 10;

Temperature: Keep between 21 – 25°C;



Omnivorous. In the wild, the Danio Erythromicron feeds on zooplankton, algae and other small creatures that fit in its mouth.

As they are omnivorous fish, they will accept rations without major problems, although most of the time they prefer foods rich in protein. Also, it will be very difficult to see these fish going to the surface to get food. Therefore, it is best to provide live or frozen foods such as brine shrimp.

Providing the Danio Erythromicron with a high protein diet ensures better coloring and also encourages spawning.

Below, check out some excellent feeds available for these fish. If you want to buy them, just click on their respective links:

Temperament / Behavior

The Danio Erythromicron is a very peaceful, curious and active fish, but it is not a true schooling fish. So don’t expect to see him swimming along with others of his kind.

Most of the time you will see these fish investigating every corner of the aquarium. As they do not swim in schools, each will go their own way and perform their own tasks. Also, because it is a shy animal, it can be very easily frightened by people passing in front of the aquarium.

Males may fight with each other now and then, but this is for them to establish hierarchies. To minimize this behavior a little, try to keep them in large groups. I recommend that you keep these fish in groups of 15 or more..

Inadequate parameters or poor water quality, overcrowding or having a scarce number of females can also make males angry. The good news is that these fights do not result in serious injuries.


There is only one rule to follow when choosing aquarium mates for the Danio Erythromicron. Avoid large, aggressive fish that may view you as food, as well as fish that require warm water. Although the Esmeralda Rasbora is a quiet fish, any larger species might find it a good meal! Some good aquarium companions for these fish include, for example:

Sexual Dimorphism

Although they look the same during the juvenile stage, males and females differ in color saturation when they reach adulthood. Males are usually smaller than females and have more vivid colors. This applies to fins, stripes and base color. In addition, the male has orange fins, while the females have the same transparent fins.

Mating / Reproduction

The reproduction of the Danio Erythromicron happens spontaneously, without the need for the aquarist to intervene. As long as you feed your fish a high protein diet and set up a suitable environment, they are sure to breed.

Set up a small aquarium of about 15 liters and add lots of fine-leaved plants such as java moss. There is no need for light in this aquarium and you can use a simple sponge filter to provide some oxygen.

Transfer a couple or a group consisting of one or two males and several females to this set up aquarium. It is important to note that the more fish, the greater the risk of egg predation.

See too:

Spawning occurs without major problems and a single female can lay up to 30 eggs among the plants. At this point, the adults should be removed, as they will eat anything they find along the way. Also, females need a recovery period before spawning again as they are unable to produce eggs every day.

In the wild, these fish breed all year round, so if you have groups made up of several females and a few males, you are sure to have eggs and hatchlings scattered and hidden around the aquarium.

The incubation time will depend on the temperature to some extent, but most of the time it takes around 72 hours for the hatchlings to be born and 3-4 days for them to start swimming around the aquarium.

Aquarium Setup

The Danio Erythromicron is a very small fish, so you can keep a group of 15 to 20 fish in a 40 liter aquarium without any problems.

You can use a dark substrate and add lots of plants for these fish. This species loves to live in well-planted environments, as with plenty of places to hide, they will feel comfortable and safe.

Use a Hang-on filter to obtain the best results for setting up an aquarium for this species. Also make sure you pay attention to the lighting, so the plants will grow vigorously and the fish will have their colors well highlighted.

The Danio Erythromicron is a perfect fish even for beginners in the hobby, but remember that the smaller the aquarium, the greater the difficulty in keeping its parameters stable.