Fish
Scarlet Badis
Dario dario
Origin: India: lower Brahmaputra River catchment in West Bengal and Assam; shallow, slow-moving and stagnant streams and ponds
Also known as: Scarlet gem, Dario, Red badis
Fact sheet
- Size
- 2 cm
- Lifespan
- 3 years
- Minimum tank size
- 20 L
- Temperature
- 16–25 °C
- pH
- 6.5–7.5
- Hardness GH
- 5–10 °dH
- Temperament
- Semi-aggressive
- Social behavior
- Solitary
- Swimming zone
- Middle
- Diet
- Carnivore
- Jumps out
- No
- Eats plants
- No
Varieties
Overview
Dario dario, the scarlet badis, is a tiny but extraordinarily beautiful fish of the family Badidae, prized for the intense ruby-red colouration and iridescent blue vertical bars of the males. It is one of the smallest known percoid fish — females do not exceed 1.5 cm, and males reach only 2–2.5 cm. The fish inhabits shallow waters among dense aquatic vegetation, leaf litter, and root structures in West Bengal and Assam. Despite their diminutive size, males are highly territorial and perform elaborate ritual displays. An excellent choice for a nano aquarium, but the species has specific feeding requirements — it accepts only small live foods.
Appearance
Males reach 2–2.5 cm in length and display dazzling colouration: a silvery-scarlet body bearing seven vivid iridescent blue vertical bars on the flanks. Two thin dark streaks cross the eye. Females are considerably more subdued — greyish-green with paler transverse bars — and reach only about 1.5 cm. Sexual dimorphism is very pronounced and allows easy distinction of males from females even in juveniles.
Care
A minimum tank volume of 20–30 litres is needed for a small group. Water parameters: pH 6.5–8.0, hardness up to 17 dH, temperature 20–26°C (68–79°F), preferably towards the lower end of this range. The tank must be densely planted with fine-leaved plants and offer plenty of hiding spots — caves, tubes, broad leaves. Good filtration and aeration are required along with weekly water changes of 25–30%. A species-only tank or a nano setup with non-competitive, peaceful inhabitants is ideal.
Feeding
Scarlet badis is a predator with a very small mouth. It accepts only small live and frozen foods: brine shrimp nauplii, small bloodworm, daphnia, cyclops, and micro worms. Dry foods are generally completely ignored — acclimatisation is extremely difficult. Feed small portions twice daily. Insufficient feeding leads to rapid emaciation, which is the primary challenge in keeping this species.
Compatibility
Males are territorial and may aggressively chase conspecifics — a ratio of one male to 2–3 females is recommended. Not suitable for housing with active or large fish. Compatible with small, peaceful nano species: kubotai rasboras, oryziias, and other non-competitive microfish. Pairs excellently with neocaridina shrimp as it does not prey on adult shrimp. Avoid species that compete for the same small live foods.
Breeding
Sexual maturity is reached at around 5 months of age. The male prepares a spawning site (a cave, leaf, or tube) and courts the female with elaborate displays. Eggs are deposited on the underside of the shelter; the male guards the clutch and drives the female away. Eggs are small; hatching occurs in 2–3 days; fry become free-swimming after a further 7–10 days. First food is infusoria, followed by brine shrimp nauplii after 5–7 days. Fry grow slowly and require a continuous supply of live food.
Fun facts
Dario dario is the only species in the genus in which males possess exactly seven iridescent blue vertical bars, making this a reliable diagnostic feature. The species is found only in the lower Brahmaputra catchment, making it a range-restricted endemic. Despite their tiny size, males are capable of aggressively defending a territory and perform impressive courtship displays that rival those of fish many times their size.