The scarlet badis (Dario dario) is a small fish that appears to be restricted to tributary systems draining into the Brahamaputra River in parts of West Bengal and Assam states, India although it may also range into Bhutan. It typically inhabits shallow, clear water streams with sand or gravel substrates and dense growths of marginal and aquatic vegetation. This fish grows to an adult size of .5 to .8 inches long. Females are smaller, less much colorful and possess a noticeably shorter body profile than males. Males have red and blue markings and develop extended pelvic, dorsal and anal fins as they mature.
The scarlet badis prefers a temperature of 64°F to 78°F. They will do well with a pH of 6.5 to 8.5, and a hardness from 2 to 12°H or higher.
Scarlet badis should be maintained in an aquarium of 10 gallons or larger. A well planted aquarium with plenty of shelter, including driftwood (ZM2000), twisted roots, and stone caves all work well. A dark colored soft, sandy substrate (CS6631) is a good choice for bringing out the best color.
The scarlet badis is a slow moving little fish with a retiring nature, and is easily intimidated or outcompeted for food by larger or more aggressive tank mates. It is best maintained alone or with other very small species, such as pygmy cories and chili rasboras.
Males can be very aggressive towards one another, especially in confined spaces. In a small aquarium, only a single pair or one male and several females should be housed, in roomier surroundings a group can coexist provided there is space for each male to establish a territory.
Scarlet badis are micropredators feeding on small aquatic crustaceans, worms, insect larvae and other zooplankton in their natural habitat. In the aquarium it may be fed live and frozen foods. Good choices include frozen reef plankton (a small copepod)(SF8200), live blackworms, and flakes (AL165). For maximum color, growth, and health these fish will look their best when given probiotics (AL169) in addition to a balanced diet.