- Scientific Name: Danio roseus
- Synonym: Branchydanio albolineatus, Nuria albolineata
- Common Name: Purple Haze Danio, Purple Passion Danio, Rose Danio, Rosy Danio
- Family: Cyprinidae
- Origin: Laos, Myanmar and Thailand
- Adult Size: 1.25 inches (3.2 cm)
- Social: Peaceful, active, schooling fish
- Lifespan: 4 years
- Tank Level: All levels
- Minimum Tank Size: 20 gallon
- Diet: Omnivore, eats most foods
- Breeding: Egg-scatterer
- Care: Easy
- pH: 6.0 - 7.5
- Hardness: 2-15 dGH
- Temperature: 68-77 F (20-25 C)
Originating from northern regions of Laos and Thailand, and more recently Myanmar, this species is relatively new to the aquarium trade being first described in 2000. Since that time it has quickly become popular due to a modest price tag, attractive appearance, peaceful nature and ease of care. Since it's introduction this species has been crossbred with the Pearl Danio - Danio albolineatus, resulting in hybrids that can sometimes be difficult to distinguish from either originating species.
Similar in appearance to Pearl Danios, the Rosy Danio is often mistaken for it's cousin. Similar features include a pearly iridescent color, upturned mouth and a forked tail. Immature specimens are steely blue in color, while fully mature adults display a rose colored belly, giving rise to their name. The Rosy Danio differs from the Pearl Danio in several subtle ways, being more slender, having two pairs of long barbels, and lacking dark horizontal stripes located posteriorly along the sides. Like other Danios, this species is an active schooling fish that is most comfortable in a school of at least a half dozen of its own kind, more if space allows. Males will display the most vibrant colors when females are present.
Rosy Danios are extremely peaceful and can be kept with many other species of fish. They make an excellent community fish, and will tolerate a wide variety of water conditions. Perhaps the only thing to consider when choosing tank-mates is to avoid large fish that might decide to make a meal of the Rosies. They are very active, and can serve as dither fish as long as they are not kept with very large or aggressive fish. Tetras, other Danio species, Catfish, and other small to medium sized peaceful fish can eb kept with Rosy Danios. Keep in mind that you will need to keep at least a half dozen, as they are a schooling fish.
Rosy Danios are quite adaptable to a variety of aquarium habitats, making them an excellent choice for a community aquarium setup. A live planted aquarium will make them feel at home, but is not required, as they will adapt to many environments. Provide some open swimming space, and make sure the tank is well covered, as this species will jump. Due to their light coloration, a dark substrate is best to show off their colors and mimic their natural river/stream native habitat. Water parameters are not critical, however they do prefer soft water that is acidic to neutral in pH.
In their natural habitat the diet of the Rosy Danios consists primarily of insects an their larvae. However, they will readily accept any food, from flake to freeze-dried o pelleted foods. For optimal health and coloration, provide them with live or frozen live foods periodically. Bloodworms, Brine Shrimp and Daphnia are all excellent live food choices, and will bring out their colors. Live foods are also ideal when conditioning for breeding.
Female Rosy Danios have a deeper body and generally grown larger than their make counterparts. Fully mature males will display a brilliant rosy belly, particularly when ready to spawn.
Rosy Danios are relatively easy to breed. Like other Danios, they are egg-scatterers and will consume their own eggs if allowed to. To increase the survival rate of the eggs and fry, provide a large amount of fine-leafed vegetation, such as Java Moss. Alternatively, spawning mops may also be used to provide cover Another method is to use a large grade mesh in the bottom of the tank, that will allow the eggs to drop through but block the adults from reaching them. Adults can also be removed from the spawning tank to ensure greater brood yield.
The water should be acidic to neutral, and temperature in the upper 70's. Condition the breeders with live foods. The females will become noticeably fatter when they are ready to spawn. Adding small quantities of slightly cooler water will help trigger spawning, which usually occurs near dawn. Up to several hundred eggs will be scattered, and will hatch in 24 to 36 hours. The fry will initially feed on infusoria or commercially prepared fry foods. moving on to freshly hatched brine shrimp as they grow larger.