The dwarf spotted danio is a hearty little fish from Myanmar that has had a long history in the aquarium industry. The earliest written descriptions of the spotted danio are from 100 years ago. Since the 1960s, the export of this fish was affected dramatically by the political instability in what was then called Burma. In recent years, the country has stabilized, and this beautiful fish has started to make a comeback in the aquarium trade.
Common Names: Dwarf danio, dwarf spotted danio, spotted brown, spotted danio
Scientific Name: Danio nigrofasciatus
Adult Size: 2 inches, usually smaller
Life Expectancy: 3 years
|Social||Peaceful schooling fish|
|Tank Level||All levels|
|Minimum Tank Size||10 gallon|
|pH||6.5 to 7.0|
|Hardness||5 to 12 dGH|
|Temperature||74 to 82 F (24 to 28 C)|
Origin and Distribution
This species originates from the lakes, streams, rivers, rice paddies, and various still bodies of water in Myanmar. The range of this species is relatively limited, having been found only in the central regions of the country, where it is primarily a seasonal fish. During dry periods of the year, water sources dry up, and this fish diminishes in number. When the monsoons come, bringing copious amounts of water with them, fish populations rebound.
Colors and Markings
Although bearing several similarities to its cousin, the zebra danio, the spotted danio is smaller and less active. Overall this is a smaller danio species, rarely reaching more than 1.5 inches in length. The body is silvery in color and iridescent under good lighting. The most defining features of this species is a single bold dark stripe that runs from gill to tail, turning bluer in color as it nears the tail. This stripe narrows when it reaches the tail, but continues through the tail fin. Above this stripe is a white stripe, which in turn is bordered by a much thinner dark stripe that is the same color as the primary dark stripe. The small stripe often breaks up into a series of small spots as it reaches the area of the tail.
Below the primary dark stripe is a series of small spots that cover the lower part of the body. The fins are relatively colorless for the most part, except for the strip on the tail fin, as well as spots on the anal fin. These spots on the anal fin are a means to identify this particular species. In addition to spots, the anal fin also is edged in pale brown. The brown anal fin edging is more predominant in males than females.
Spotted danios are a peaceful species that get along with other species. However, they are rather timid. This, combined with their diminutive size, limits their suitability for community aquariums. They will do well when kept with other small species, particularly those from the same part of the world. This includes the glowlight danio and panther danio, among other species originating from Myanmar.
Small tetras and rasboras are also suitable tankmates, as well as cory catfish. Spotted danios should always be kept in schools of at least a half dozen, preferably more if possible. The larger the school, the less timid this species will be.
Habitat and Care
Spotted danios are most comfortable in a habitat that is similar to their native conditions. They prefer a well-planted aquarium, using live plants if possible, but artificial will do. A dark substrate is ideal for showing off the lighter colors of this species. Overhead lighting will also bring out their delicate coloration. Provide some bogwood and rocks to complete the river type of habitat from which they hail. The aquarium should have a well-fitted cover; this species is inclined to jump.
Water conditions are not extremely critical, but they are sensitive to build up of toxins, so regular water changes are recommended. Soft to moderately hard water is suitable, with an acidic to neutral pH. Like many other types of danios, this species can tolerate cooler water temperatures, but when breeding, warmer temperatures are recommended.
This species is omnivorous and will accept almost any food, including flakes, small pellets, freeze-dried, and frozen foods. They particularly relish small live foods, which should be provided as supplemental food when possible. In place of live food, use frozen bloodworms, brine shrimp, and daphnia or mosquito larvae.
Spotted danios will feed in the upper portion of the tank, but are rather timid, and may not compete well for food with boisterous fish. If they are in a tank with more active species, take care to ensure the spotted danio is receiving its fair share of the food. Use multiple feeding rings to help distribute food more evenly among tankmates.
Females are larger overall than males and have a rounder body. The slimmer male is more brightly colored, while females have more subdued coloration. In males, the anal fin has a golden tint with a light brown edging. When well-conditioned for spawning, the male becomes even more vibrantly colored, while the female will become rounder in the belly as she fills with eggs.
Spotted danios are relatively easy to breed. In some cases, they may spawn without providing special accommodations. You may not even be aware that spawning has taken place. However, they are voracious egg and fry eaters. If the owner wishes to raise most or all of the spawn to adulthood, a separate tank is needed to ensure survival.
A separate breeding tank can also serve as a grow-out tank. This tank should be set up with a matured sponge filter, and filled only half to two-thirds full with water in the range of 77 to 79 F (25 to 26 C). Lighting should be dim, and the tank should be equipped with either a spawning mat or plenty of fine-leafed plants, such as Java moss. Alternatively, mesh or marbles can be used on the bottom to allow the eggs to fall out of reach of the adult fish.
Condition the breeders with live foods before spawning. When the breeders are ready, place two males and one female in the prepared tank. Males will actively court the female, eventually resulting in the female beginning to deposit eggs. A dozen or so are released at a time, with a maximum of only a couple hundred, usually far less. Promptly remove the adult fish once they finish laying eggs. In approximately 24 to 48 hours, the eggs will hatch, or sooner if the water temperature is higher. Lighting should be kept very dim, as the fry are sensitive to light.
After a couple of days, the fry will become free-swimming. Initially, they will feed on infusoria, then move to freshly hatched brine shrimp. If unable to provide infusoria, use a commercially prepared fry food, feeding them frequent small meals. As the fry grow, larger foods can be fed to them.
Interestingly enough, there has been reported cross-breeding between this species and pearl danios, as well as other species of danio. However, the fry produced from these crosses are usually infertile.