Blue danio
Danio kerri
FreshwaterFish
Care at a glance
- Temperature
- 68–79°F
- 20–26°C
- pH
- 6.0–7.5
- Adult size
- 1.8 in
- 4.5 cm
- Minimum tank
- 11 gal
- 40 L
- Temperament
- Peaceful
- Social behavior
- Schooling
- Swim level
- Middle
- Difficulty
- Beginner
- Breeding
- Medium
- Rarity
- Rare
- Family
- Cyprinidae
- Origin
- Thailand
Overview
Keep them in a group of six or more, ideally more, since they settle down and look better in numbers. They're fast, active swimmers that hang in the upper half of the tank. Aim for around 40 liters minimum, pH from 6 to 7.5, and temperatures between 20 and 26 C. They're peaceful and easy to feed: good flake, small pellets, and frozen brine shrimp or daphnia a few times a week.
In the wild
Blue danios come from clear, gently flowing streams in Thailand and nearby parts of Southeast Asia, often over sand and rock with plants along the edges. The water there runs soft and a little acidic to neutral. Give them open swimming room up top, some current from the filter, and a temperature in the low to mid 20s C.
Good to know
This is a small cyprinid, reaching about 4 to 5 cm as an adult. It's an egg scatterer with no parental care, and eggs usually hatch in a day or so. Wild stocks are stable, though deforestation and pollution are the usual long-term concerns for stream fish like this one.
Did you know
Danio kerri was first described from Thailand's Ko Yao islands, and it's a close relative of the zebra danio. The two will sometimes hybridize in aquariums if you keep them together without enough of their own kind.
Weekly picks
Tank mates
Blue danio is a peaceful, schooling species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Wandering snail
Ampullaceana balthica
Freshwater0.8 in (2 cm) · 11 gal (40 L)50–84°F (10–29°C)
Golden dwarf sucker
Otocinclus macrospilus
Freshwater1.4 in (3.5 cm) · 11 gal (40 L)70–79°F (21–26°C)
Sicklefin livebearer
Girardinus falcatus
Freshwater2.6 in (6.5 cm) · 11 gal (40 L)68–82°F (20–28°C)
Jewel killifish
Aphyosemion exiguum
Freshwater1.6 in (4 cm) · 11 gal (40 L)68–77°F (20–25°C)
Cheetah moth catfish
Pseudolaguvia shawi
Freshwater1.5 in (3.8 cm) · 11 gal (40 L)68–79°F (20–26°C)
Dubois' panchax
Epiplatys duboisi
Freshwater1.4 in (3.5 cm) · 11 gal (40 L)68–77°F (20–25°C)
Common questions
What size tank does a Blue danio need?
A Blue danio needs at least 11 gal (40 L). It spends most of its time in the middle.
What temperature and pH does a Blue danio need?
A Blue danio is comfortable at 68–79°F (20–26°C) with a pH of 6.0–7.5.
How big does a Blue danio get?
An adult Blue danio reaches about 1.8 in (4.5 cm).
Does a Blue danio need a group?
Yes. A Blue danio is a schooling species and should be kept in a group, not singly.
Related species
1.5 in (3.7 cm)11 gal (40 L)64–79°F (18–26°C)Spotted danio
Danio nigrofasciatus
1.5 in (3.7 cm) · 11 gal (40 L)
2.4 in (6 cm)18 gal (70 L)61–77°F (16–25°C)Pearl danio
Danio albolineatus
2.4 in (6 cm) · 18 gal (70 L)
1.2 in (3 cm)11 gal (40 L)64–79°F (18–26°C)Gold ring danio
Danio tinwini
1.2 in (3 cm) · 11 gal (40 L)
2 in (5 cm)15 gal (55 L)64–75°F (18–24°C)Zebra danio
Danio rerio
2 in (5 cm) · 15 gal (55 L)
0.8 in (2 cm)9 gal (35 L)72–79°F (22–26°C)Celestial Pearl danio
Danio margaritatus
0.8 in (2 cm) · 9 gal (35 L)
0.8 in (2 cm)11 gal (40 L)68–75°F (20–24°C)Emerald dwarf rasbora
Danio erythromicron
0.8 in (2 cm) · 11 gal (40 L)
