Blue Danio, Kerr`s Danio (Danio kerri) — 3-3,5cm

Overview

The Blue Danio (Danio kerri), also known as Kerr's danio or turquoise danio, is a small, shimmering, peaceful danio that brings constant movement and color to planted community aquariums. Native to Thailand, especially slow-moving streams and tributaries in the southern part of the country, this species reaches just 3.5 cm in length and is prized for its iridescent blue-green coloration and easy care requirements. The body displays a pale greenish-blue to turquoise base overlaid with darker markings and an iridescent sheen. Unlike some larger danios, the Blue Danio is perfectly suited to smaller planted aquariums and nano community setups. Available for sale UK from specialist suppliers, this species brings elegance, activity, and visual interest to any well-planted aquarium.

Appearance and Physical Characteristics

Danio kerri exhibits a streamlined body with a deeply forked caudal fin. The body displays a pale greenish-blue to turquoise base overlaid with darker vertical bars or spots and an iridescent blue-green sheen that shimmers under aquarium lighting. The fins are generally clear to faintly tinted. Males are typically more slender and more intensely colored, while females are fuller-bodied when gravid. Both sexes have large eyes and a slightly upturned mouth. The shimmering blue effect is most pronounced under good lighting in well-fed, unstressed fish.

Natural Habitat and Distribution

Danio kerri is native to Thailand, especially slow-moving streams and tributaries in the southern part of the country. They inhabit areas with submerged vegetation, roots, and overhanging grasses. The substrate is typically sandy or muddy, and water chemistry ranges from soft to moderately hard with slightly acidic to neutral pH (6.0-7.5). Temperatures are moderate (20-25°C). These fish are surface-oriented and found in loose shoals near the surface.

Aquarium Setup and Environment

A minimum aquarium capacity of 60 liters is recommended for a school of 8-10 Blue Danios. Provide planted areas and open swimming space. A dark substrate enhances coloration. Include driftwood and floating plants. Filtration should be gentle to moderate. A tight-fitting lid is essential, as danios are active jumpers.

Water Parameters and Quality

Blue Danios thrive in clean water. Maintain temperatures between 20-25°C, with 22-23°C optimal. The pH should range from 6.0-7.5. Water hardness can vary from soft to moderately hard. Maintain zero ammonia and nitrite, and keep nitrates below 20 ppm through regular water changes.

Feeding and Nutrition

Danio kerri is an omnivore. Offer varied diet of high-quality micro pellets or flakes supplemented with small frozen or live foods such as daphnia, brine shrimp, and mosquito larvae. Feed twice daily in small portions.

Behaviour and Temperament

The Blue Danio is a peaceful, highly active species that spends most of its time in the upper levels of the aquarium. They are genuinely peaceful. Best kept in shoals of 8-10+ individuals. They are diurnal and most active during daylight hours. Their shimmering blue coloration and lively movement make them engaging.

Tank Mates and Compatibility

Suitable tank mates include other small peaceful danios, small rasboras, small tetras, Corydoras catfish, and Otocinclus. Avoid large predatory fish, aggressive cichlids, fin-nipping species, and very slow long-finned fish.

Breeding

Danio kerri is an egg-scattering species that will spawn among fine plants or spawning mops. Adults should be removed after spawning because they may eat the eggs; fry need very small live foods or infusoria at first, then newly hatched brine shrimp.

Why Buy from Tropical Fish Co

Tropical Fish Co is the UK's trusted source for healthy Blue Danios. Every fish is quarantined, conditioned, and health-checked. We offer a live arrival guarantee, secure packaging, and next-day delivery. Order today.