Maximum size : 4.5 cm

Blue Danio - Danio kerri : Complete Fish Profile & Care Guide

Table of contents


Blue Danios (Danio kerri) epitomize the perfect harmony of tranquillity and resilience, making them an excellent choice for aquarists, particularly those new to the hobby. Their peaceful and hardy nature and adaptability to varying water conditions set the stage for seamless integration into your aquatic haven. Rest assured that these friendly companions will not disrupt or pose a threat to larger tank inhabitants, ensuring a harmonious coexistence.

The availability of Blue Danios within the aquarium trade is relatively abundant, granting enthusiasts the opportunity to easily acquire these captivating fish. However, in order to unlock the full potential of their natural behaviour and enhance the visual spectacle, it is advisable to maintain Blue Danios in groups of eight or more individuals. This not only mitigates their skittish tendencies but also fosters a more cohesive and awe-inspiring display as males flaunt their captivating colours while vying for female attention.

Blue Danios showcase their versatility by harmoniously cohabiting with various popular aquarium fish. Complement their presence with suitable tankmates such as small Cyprinids, Tetras, Livebearers, Rainbowfish, as well as Loaches and Catfish. When designing the perfect habitat for Blue Danios, aim for a heavily planted aquarium that artfully mimics the serene flow of a stream or river. Employ a darker substrate to accentuate their vividness, as they may appear paler in a sparsely adorned environment. Enhance the aesthetic appeal by incorporating gravel, smooth stones, or varied-sized rocks. Additionally, the inclusion of driftwood branches and roots, alongside hardy aquatic plants like Anubias, Bolbitis, or Microsorum, offers both visual allure and convenient surfaces for attachment.

To meet their preference for clean, well-oxygenated water, prioritize effective filtration within the aquarium setup. Facilitate a gentle current traversing the tank, allowing Blue Danios to navigate gracefully and purposefully. Filter outlets or supplementary powerheads can aid in creating the desired flow; however, it is crucial to avoid overly turbulent conditions, as these Danios naturally gravitate towards calmer stretches in their native habitats. Finally, exercise caution and ensure the security of your aquarium with a tight-fitting lid, as members of this genus possess impressive jumping capabilities and can navigate even the smallest gaps.

Admire the stunning physique of Blue Danios, characterized by slightly deep, torpedo-shaped bodies that exhibit either a powdery-blue or yellowish-green hue, continuing into the caudal fin, influenced by their specific geographic origins. Furthermore, delicate pinkish-gold lateral stripes elegantly extend from their opercle to their caudal peduncle, adding a touch of ethereal beauty to their overall appearance. Notably, the colouration of Blue Danios may vary among populations from different localities, with northern populations tending towards a more pronounced blue shade, while their southern counterparts lean towards a distinguished yellowish hue.

Elevate your aquatic realm with the captivating presence of Blue Danios, an embodiment of serenity and resilience that brings an exquisite touch of natural beauty to your aquarium. With their alluring colours and tranquil demeanour, these remarkable fish are poised to captivate and inspire both novice and seasoned aquarists alike.

Blue Danio Photos

Sexual Dimorphism

Discerning between male and female Blue Danios is a task of relative ease. Adult males exhibit a slighter and more slender physique compared to females while boasting a striking vibrancy in their colouration. These visually captivating males come alive with their resplendent hues, accentuating their presence during spawning conditions. Conversely, sexually mature females typically display a larger and more rounded abdomen, accompanied by a comparatively subdued colouration. These distinct physical disparities become more apparent when the fish are in the midst of their spawning preparations, enabling observers to discern the unique characteristics that define each gender within this remarkable species.

Quick Facts

Scientific NameDanio kerri
Year Described1931
Other NamesKerr's Danio, Turquoise Danio
Max Size4.5 cm
Aquarium LevelMiddle - Top
DifficultyBeginner - Intermediate
Best kept asGroups 8+
Diet & FeedingOmnivore
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
pH 6.5 - 7.5
GH 8 - 12
TDS 36 - 215
Ideal Temperature
72 - 78
22 - 25

Natural Habitat

Embark on a captivating journey to the mesmerizing landscapes of Koh Yao Noi island, nestled within the scenic Phang Nga province of southwestern Thailand. It is here that the remarkable Blue Danios claim their rightful place as native inhabitants. However, with their undeniable allure, these enchanting fish have also been documented on other picturesque islands, including Ko Lanta, Langkawi, Phuket, and the mainland of southern Thailand.


Blue Danios, akin to many Cyprinids, employ an egg-scattering reproductive strategy whereby they exhibit no parental care towards their offspring. Under favourable conditions and optimal health, these fish frequently engage in spawning activities. In a well-established aquarium with dense plant coverage, the emergence of a small number of fry may occur spontaneously, requiring minimal intervention. However, should you seek to augment the fry population, a more controlled approach is warranted.

Begin by conditioning the adult group together while simultaneously setting up a dedicated breeding tank, which should be half-filled with water. Create a dimly lit environment within the breeding tank and ensure the bottom is covered with a mesh of appropriate grade—wide enough for eggs to pass through, yet small enough to prevent adult fish from accessing them. Alternatively, plastic grass matting or an abundance of fine-leaved plants, such as java moss, can yield favourable results. The water parameters should be relatively soft and slightly acidic to neutral, with the temperature set towards the upper end of the suitable range.

For initial filtration, introduce a small air-powered filter positioned to direct the current down the entire tank length. Alternatively, consider utilizing a mature sponge-type filter. Once the adult fish are well-conditioned and the females exhibit a noticeable fullness of eggs, introduce one or two pairs into the separate breeding tank. To stimulate spawning, provide small amounts of live and frozen foods to the pairs while gradually adding small quantities of cold water at regular intervals, effectively topping up the tank. Spawning typically occurs the following morning. A simple method to discern if the female has successfully spawned is to observe if she appears noticeably slimmer. As adults tend to consume any eggs they encounter, removing them after a couple of days is advisable. In addition, the transition from a power filter to a sponge-type unit at this stage prevents fry from being inadvertently drawn into the filtration system.

The incubation period of the eggs is influenced by temperature to a certain extent. Generally, it takes approximately 24 to 36 hours for the eggs to hatch, followed by 3 to 4 days until the young become free-swimming. Initially, nourish the fry with Paramecium or a finely graded dry food. Then, as the fry grows and develops, gradually introduce them to microworms and baby brine shrimp, offering increasingly substantial sustenance to support their healthy growth.

By implementing these controlled breeding techniques, you can actively participate in the growth and propagation of Blue Danios, observing the remarkable journey from eggs to free-swimming fry as they flourish under your attentive care.

Diet & feeding

Blue Danios exhibit a versatile palate within the confines of an aquarium, displaying an accommodating disposition towards various food options. While they are generally receptive to a wide range of sustenance, incorporating a high-quality dried product such as flakes or granules as the foundation of their diet is recommended. To further enhance their nutritional intake, it is advisable to provide regular servings of small live and frozen delicacies, including bloodworms, mosquito larvae, daphnia, and brine shrimp. These delectable offerings will be eagerly accepted by the Danios, promoting their overall well-being and satiating their appetite.

Furthermore, offering the occasional vegetable treat serves as a delightful addition to their dietary regimen. Introducing suitable plant-based options, carefully selected to cater to their specific nutritional needs, will be met with appreciation by these captivating fish.

By ensuring a balanced and varied diet, you not only cater to the dietary requirements of Blue Danios but also contribute to the vibrancy of their colours and the preservation of their optimal health.

Other Danios of interest