FishFreshwaterAdvanced
Scarlet Badis
Dario dario
The Scarlet Badis is a breathtaking, micro-predatory jewel from India. Perfect for peaceful nano-aquariums, it requires dense vegetation, slow currents, and a strict diet of live micro-foods.
Water Temperature
18 - 26 °C
pH Value
6.5 - 7.5
Water type
Freshwater
Tank level
Bottom and middle
Adult size
2 cm
Minimum tank volume
>= 30 L
Minimum group
>= 1
GH
5 - 15 dGH
KH
2 - 7 dKH
TDS
95 - 295 ppm
Conductivity
148 - 461 uS/cm
Species description
Geographical Origin and Habitat: Northeast India (Brahmaputra basin, West Bengal). Inhabits slow ditches, calm pools and clear shallow waters saturated with patches of extremely dense vegetation.
Taxonomy and Morphology: Scarlet Badis (Dario dario). One of the smallest freshwater vertebrates in the world (often under 2 cm / 0.8 inches). Belongs to the Badidae. Sedentary character and "jerky" movement like a hummingbird.
Social Behavior: Micro-fish with the temperament of a dwarf Cichlid. Males establish very small defined territories and fiercely defend them in spectacular displays towards each other. Only one male per tank (with females) is recommended unless you have over 60 cm (24 inches) of space.
Coloration and Sexual Dimorphism: The male is an absolute jewel: seven vibrant red vertical bands alternating with silver-blue bands. The fins are bright red edged in ice white. Females are tiny, stocky, and almost entirely gray, lacking red pigment (impossible to find in shops).
Care, breeding and tankmates
Aquarium Setup: The king of nano-aquariums (20-30 liters / 5-8 gallons are sufficient for a pair). Absence of vigorous current. Plant every square inch: rocks encrusted with moss, ferns (Microsorum), carpets and Cryptocoryne. Lots of shelters are vital.
Diet and Feeding: Critical point: it is a micro-predator that will almost always ignore dry feeds. Feed daily with tiny LIVE prey (Daphnia, Microworms, Grindal, brine shrimp nauplii). With dedication it accepts frozen foods (bloodworms) waved in front of its nose.
Water Quality: Prefers cool subtropical temperatures (18-23°C / 64-73°F). Tanks heated to 27-28°C (81-82°F) drastically shorten its life. Very clean water and very slow sponge filters so as not to affect oxygenation.
Compatibility and Cohabitation: To be kept strictly alone or with very few equally shy nano tankmates (e.g. Boraras brigittae). Adult Caridina shrimp are safe, but it will systematically eat the "zoeae" (baby shrimp).
Aquarium Breeding: A receptive female enters the male's bush (territory). After the embrace, she lays a single adhesive egg which the male will defend. Microscopic fry demand Infusoria or live paramecia.
Risks and Diseases: Extreme thinness and deadly wasting due to food competition with tankmates. Fake females (submissive males who lose their colors so as not to be killed) complicate reproduction.
Geographic Origin and Distribution
Northeast India (Brahmaputra basin, West Bengal). Inhabits slow ditches, calm pools and clear shallow waters saturated with patches of extremely dense vegetation.
Origin
South and Southeast Asia
Fish profile
- Temperament
- Semi-aggressive
- Males of the species are highly territorial toward one another and will display fiercely, flaring their fins and engaging in brief skirmishes to defend their chosen patch of the aquarium. Despite this intra-species aggression, they are generally peaceful, almost to the point of being excessively shy, toward other fish species. Their timidity requires an aquarium environment with plenty of hiding spaces and a lack of boisterous tank mates to prevent them from becoming completely withdrawn.
- Diet
- Omnivore
- Dario dario are obligate micro-predators that can be exceedingly fussy eaters, often outright refusing to accept any form of dry flake or pellet food. Their diet must consist almost entirely of small live foods, with microworms, daphnia, baby brine shrimp, and grindal worms being essential for their survival and health. While some individuals can be slowly weaned onto frozen foods, live prey is always the most reliable way to ensure they receive adequate nutrition.
- Life expectancy
- 3-4 years
- In captivity, Dario dario usually lives for 3 to 4 years when kept under proper care and target feeding. Keeping the water clean and stable is fundamental for their long-term health. Careful maintenance helps prevent common diseases to which they are sensitive.
- Adult size
- 2 cm
- The catalog's scalar value is 2 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 1.52 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Dario dario (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Harem
- Keeping a single male with multiple females (a harem) is the ideal setup, as this disperses the male's aggressive territorial behavior and mating attempts. Putting multiple males in a small nano tank is generally not advised, as they will fight relentlessly over territories, leading to severe stress or death for the subordinate males. If keeping multiple males, a significantly larger aquarium with abundant line-of-sight breaks and distinct territories is absolutely mandatory.
- Feeding frequency
- Twice daily
- Because they are slow, deliberate hunters rather than aggressive feeders, they benefit from small, targeted feedings once or twice a day. When providing live foods, it is crucial to ensure that the food items reach the bottom or the dense vegetation where the badis spend most of their time hunting. Observing them during feeding time is highly recommended to confirm that they are successfully catching and consuming enough food.
- Bioload
- The Scarlet Badis produces an extremely low bioload due to its maximum adult size of little more than three-quarters of an inch. A single male or a small harem can easily be housed in a well-maintained nano aquarium of 5 to 10 gallons without significantly impacting water quality. However, their specific dietary needs often require the regular introduction of live foods, which can independently increase the organic load on the tank if uneaten portions die and decay.
- Flow
- Stagnant
- In their native habitats of slow-moving streams and shallow, heavily vegetated pools in India, they experience very little water movement. They strongly prefer a slow, gentle flow in the home aquarium, as strong currents will quickly exhaust these tiny fish and force them to hide constantly. Using a sponge filter is ideal, as it provides excellent biological filtration while maintaining the calm, stagnant water conditions they thrive in.
- Reproduction
- Oviparous
- Breeding Dario dario is relatively straightforward if both sexes are present, though finding females in the aquarium trade can be notoriously difficult due to their drab coloration. Males will establish and vigorously defend a small territory, usually centering around a dense clump of fine-leaved moss or plants, where they entice females to spawn. After the eggs are laid and fertilized, the male will guard the territory, but will not actively care for the eggs or the resulting fry, which must be fed microscopic infusoria.
- Compatibility & tankmates
- While generally peaceful towards other species, they are extremely timid and are easily outcompeted for food by faster, more aggressive tank mates. They do best in a species-only nano tank or housed alongside very peaceful, slow-moving nano fish such as Boraras species or small Corydoras. Caution must be exercised when keeping them with ornamental shrimp, as adult Scarlet Badis may actively hunt and consume juvenile shrimp.
- Tank level
- Middle/Bottom
- These tiny predators are bottom to mid-level dwellers that spend the majority of their time meticulously inspecting plants, substrate, and hardscape for microscopic prey. They are rarely seen in the open upper levels of the water column, preferring to stay close to cover where they feel secure. Providing an environment rich in leaf litter, aquatic mosses, and dense plantings will keep them in their preferred habitat zones and encourage natural behaviors.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 3 ± 0.4 se
- Phylogenetic uniqueness (PD50)
- 0.502
- Bayesian Length-Weight
- a = 0.00389, b = 3.12
- VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.
