A peaceful omnivore cyprinidae from South Asia (India and Bangladesh) — beginner-friendly.
Care parameters
Water temperature
18–24 °C
pH
6–8
GH hardness
5–19 dGH
Adult length
2.7–3.8 cm
Minimum tank
38 L
Water layer
Mid-water swimmer; keep 6+
Difficulty
Easy
Temperament
Peaceful
Origin
South Asia (India)
Species overview
Danio rerio is a Cyprinidae from South Asia (India). In the wild it prefers clear streams, rivers and still waters; in the aquarium it stays peaceful. Plan on 2.7–3.8 cm of adult fish at 18–24 °C. Related profiles: Danio margaritatus, Danio albolineatus, Danio choprae.
Native biotope
Habitat
Clear streams, rivers and still waters
Flow
Moderate flow
Dissolved O₂
Average oxygen needs
Aquascape & hardware
Substrate
Smooth gravel and sand with open floor space
Hardscape
Driftwood, water-worn stones and shelters that mimic the native biotope
Plants
Hardy plants on hardscape; keep the floor open
Temperament, diet & tankmates
Schooling
Keep 6+; larger groups settle better
Diet
Omnivore; quality prepared foods with variety
Recommended tankmates
Amur False Gudgeon — Similar size and water needs
China-Bitterling — Similar size and water needs
Acanthorhodeus chankaensis — Similar size and water needs
Avoid keeping with
Large aggressive cichlids — Bullying and injury risk
Known fin nippers — Constant stress and fin damage
Breeding & notes
Sexual dimorphism
Males are typically slimmer and more intensely colored; females fuller-bodied
Breeding method
Egg-scatterer over fine plants; condition with rich foods and simulate seasonal changes
Frequently asked questions
Are the neon ones the same species?
Yes — GloFish and other fluorescent varieties are selectively bred or genetically derived D. rerio. Care is identical; only the color differs.
Why do my danios chase each other constantly?
That is normal social behavior — sparring and courting within the shoal. It becomes a problem only if one fish is cornered and beaten, which proper group size and space prevent.
Can they live in a community tank?
Excellently, with other active, similar-sized fish. Avoid pairing them with slow or long-finned species whose lives they will make hectic.
Why are my danios chasing one fish in circles?
That is usually spawning behavior — a male courting a ripe female — harmless in itself, though repeated harassment suggests too few females in the group.