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Blue Danio Overview, Care, Tank Setup & Breeding Guide

Small fish for your aquarium? That sounds nice. Blue Danio is an ultimate option if you’re looking for peaceful but attractive small fish that can live up to four years. It’s an adorable fish with eye-pampering behavior and easy care in general.

Blue Danio or Danio Kerri is a popular small fish native to the Malay Peninsula and also found in Thailand.

It can grow only up to 2 inches and would fit 20-30-gallon tanks very well when kept in a group of six to eight specimens. It’s a hardy little aquarium fish that can thrive on a wider range of water parameters and require easy care.

Species Overview

Level of CareEasy
AppearanceBeautiful blue turquoise color body with active schooling behavior
Life Expectancy3-5 years
SizeUp to 1.7 inches 
Tank Size30-gallon or larger
Tank EnvironmentIt can thrive and adapt to a wider range of water parameters but need a separate breeding tank
Tank MatesBetter kept in a group of six or eight
Get along well with other peaceful species like tetras or catfish

Also known as the Brachydanio Kerri, these are hardy little aquarium fish in the family Cyprinidae, already popular among aquarists. 

They species are native to some parts of SouthEast Asia where they live in the streams and surrounding pools. The small fish has beautiful coloration and can grow up to 2 inches which make it perfect for smaller aquariums.

These are friendly species that won’t attack larger species when kept in the same tank. The species better live in larger shoals or at least, in a group of eight specimens in an aquarium. It has become a popular aquarium fish due to its adaptability and hardiness making it no hassle when cared for in the tank.

It would typically form schools or shoals with each other or even with other species in the same environment. 

The fish can live up to six years even though the standard lifespan is somewhere between two and four years. As the tropical species, these fish can comfortably live in the warmer water even though they can tolerate cooler temperatures.

Despite being peaceful, they live well on a plantation that provides aquarists with more flexibility in decorating their tank.

In their native habitats, they are typically found in areas with dense vegetation. Their native environment usually has some plantations and open water space.

When kept in the community aquariums, they still show the same behavior in the wild. While they may spend most of their time swimming near the surface, they’d occasionally swim to the bottom of the tank to grab some sunk food. Blue Danios are curious species that would nibble on anything new entering their community tank.

Blue Danio Types

Blue Danio is one of ten Danionin species that are available for aquarium trades. While these have gained huge popularity, aquarist also take some other Danionin species for their tanks these include :

Zebrafish in aquarium
Zebra Danio

These species have the same shape and structure but they have different coloration and motifs. They also require similar caring for each other except for some exotic species.

Danionins are generally peaceful species that can get along with each other in a community tank but you need to keep a school of six or eight for each species.

Tank Setup

In general, the tank requirements and setup are considerably minimum but the proper setup would keep your fish living long and well. The ideal aquarium setup is, of course, to mimic their natural environment. You can follow our tank guidelines below.

As tropical fish, these prefer warm water with their adaptability. You can set up the water temperature somewhere between 18° – 26° C(64.4° – 79° F). 

For keeping up with these parameters, you’d need to invest in a thermometer and thermostat for your tank setup.

As a hardy aquarium fish, you can set the water hardness at 2 -12 dKH and configure the acidity at pH 6.5 – 7.5 for the best environment.

Partial water changes should be done regularly to keep the water quality. You can maintain and improve the water quality with a good filtration system for your tank.

Blue Danios are small fish but you need at least a 30-gallon aquarium for a school of six fish.

A larger tank is always better, especially to provide them with more space for swimming and schooling. On the other hand, you’d likely need a larger aquarium if you want to keep larger groups of these fish.

By copying their natural environment, you can decorate the community aquarium with vegetation.

Since they’re safe with plants, you can set up a densely planted area but be sure to leave them an open area for Blue Danios to swim around. Generally speaking, this fish species can live well in a moderate tank setup with natural vegetation sets.

When it comes to the aquarium environment, you need to maintain the quality by installing a good filtration system and water oxygenation.

As you’ve set up plants and are keeping a lot of these in your aquarium, then they’d need a higher oxygen level in the water. 

Since this setup may drive algae creation in the aquarium decoration, you better add herbivore tank mates that love to eat the algae.

As tropical species, daylight exposure was once very important in their native habitats. Except that you can posit the algae under the sun exposure, you must set proper lighting so they can thrive. It doesn’t have to be sophisticated as medium-light would work well.

Tank Mates

Blue Danios should be kept in a school of six to eight fish in the same tank. They can get along well with small or large species as long as they’re not aggressive. They are very active and good swimmers so they may occupy most parts of the community tank.

As they’re schooling fish, you should never leave individual Blue Danio in the tank as they would be stressed out from being alone. If you add more of these into the community aquarium, it would not only boost their active schooling but also intensify their blue colors which also indicate their readiness for mating.

Blue Danios are friendly to their tank mates but the size does matter. Since they’re considered very small fish(only 5 cm), don’t add too big species that can prey on your Danios. The tank mates should also be peaceful and not get bothered or provoked by their active schooling in the community aquarium. 

They are hardy species so they can tolerate tank mates from different species. However, there are some tank mates that are popular:

  • Tetras
  • Livebearers
  • Catfish
  • Loaches
  • Rainbowfish

With these species as you Danio’s tank mates, you can expect friendly and sometimes beneficial interactions among the tank populations. For example, Blue Danios won’t be shy to school around with those tetras or livebearers.

Diet & Food

Blue Danio fish are omnivores as you can feed them different types of foods as long as they fit their mouth. 

When you have some schools of these in a community tank you better feed them with high-quality flakes, meaty foods, larvae, frozen foods, and vegetables. 

It’s very important to supply variable diet.

You can use flakes as the main staples and use the live meaty foods or live mosquito larvae and vegetables as the supplement.

While the flakes are enough for living and breeding, the more nutritious, varied diet would improve their health, color, activeness, and lifespan.

In the end, aquarium owners are the ones who enjoy well-fed Blue Danios in their 30-gallon tanks.

3 blue danios in aquarium

Breeding Guidelines

You can differentiate males from females with their smaller size and more slender shape.

Females are generally thicker and larger.  You can even easily tell the difference between adult females and adult males. 

Generally speaking, there’s countable hardship to breed them even in a diverse community aquarium.

They can easily breed and spawn in the tank but the fry rarely survives.  Parental intervention may even reduce the chances of the fry surviving.

It should be noted that Blue Danio is an egg scatterer species so they’d simply lay or scatter the eggs around throughout the tank.

While it’s tempting, don’t interfere with the laying or the parents would simply eat their eggs before hatching. 

The best breeding conditions are the presence of morning sunlight with pairs in breeding aquariums instead of the community aquarium.

For the breeding tank setup, you can cover the bottom of the aquarium with some layers of marbles that allow eggs to sink and be protected from the parents and other adults. The breeding tank must have a robust fine-leafed plantation.

Breeders must condition Blue Danios for breeding by separating males and females a few weeks before the time to obtain the maximum amount of fry. Once the breeding tank has been set,

you can add the female first and wait 24 hours before adding the males into the tank. Otherwise, you can set up a lower water temperature to trigger them spawning in the breeding tank.

Once the spawning is completed, you can remove the adults(parents). You’d see the fry swimming around the breeding tank after one week and you can start feeding them with micro foods. Increase the size of foods gradually as they’re growing bigger.