If you're new to aquariums or just looking to add a pretty, peaceful fish to your community tank, you can't go wrong with the pearl danio. This easy-going species is hardy, easy to care for, and gets along with just about any other peaceful fish. Its iridescent colors make it unusually attractive. The pearl danio thrives in a smaller 20-gallon tank and reproduces readily in captivity.
Common Names: Pearl danio, spotted danio
Scientific Name: Danio albolineatus
Adult Size: 2 inches (6 cm)
Life Expectancy: 5 years
|Origin||Burma, Sumatra, Thailand|
|Social||Peaceful schooling fish|
|Minimum Tank Size||20 gallons|
|Diet||Omnivore, eats most foods|
|pH||6.5 to 7.0|
|Hardness||5 to 12 dGH|
|Temperature||64 to 75 F (18 to 24 C)|
Origin and Distribution
Initially imported in Europe in 1911, this species has been a popular fish in the aquarium industry ever since. They originate from clear, swiftly moving streams and rivers in Myanmar (formerly known as Burma), Thailand, and Sumatra. In nature, they feed primarily on insects and zooplankton.
This fish has several scientific names, a few of which were initially assigned to what were later determined to be color variants of the same species. Debate still exists over the classification of these differences in coloration. At one time this species was classified under the Brachydanio genus, which has since been declared invalid. The scientific name Danio albolineatus means white-lined danio.
The name of this fish should not be confused with the celestial pearl danio, also known as the galaxy rasbora, Danio margaritatus, which is a dark-colored danio sporting red or orange fins and white spots on the body.
Colors and Markings
The iridescent colors this fish is named for make it one of the most attractive of the freshwater fish. Its pearly, blue-violet hued body is accented by an orange-red stripe running from tail to mid-body. Males are smaller, slimmer, and more colorful, often showing a red tint along the ventral aspect. A yellow-ochre color variant, known as the yellow danio, is available in some locations. Pearl danios have a forked tail and two sets of paired barbels.
Pearl danios are peaceful and well-suited for community aquariums and get along with any peaceful fish. They are tolerant of a wide range of water conditions, which also makes them suited to combining with a variety of other fish. Like others of the danio family, pearls live in schools and should be kept in groups of at least five to eight, and preferably more. Males will show their best colors if there is at least one female present.
Pearl Danio Habitat and Care
Originating from fast-moving streams and rivers, the pearl danio is accustomed to strong water currents. Because they require a slightly higher oxygen level than other danios, good filtration is important. Pearl danios tolerate colder temperatures well and may even be kept in an unheated aquarium. They swim at all levels, but due to their propensity for jumping, the tank should be well covered.
An extremely hardy and easy-to-care-for fish, pearl danios make an excellent beginner fish. As they require ample swimming room, longer tanks are preferable, with plants along the back and sides. Their iridescent colors are most visible under reflected, overhead lighting, and they are particularly fond of early-morning sunlight. Although undemanding about water parameters, they do best in neutral (pH 7.0) water that is soft to slightly hard.
Pearl Danio Diet and Feeding
Pearl danios will accept all types of live, frozen, and flake food. In nature, their diet consists primarily of insects and zooplankton. To maintain health, feed good quality tropical flake or granulated food, as well as frozen and live foods such as tubifex, mosquito larvae, brine shrimp, and daphnia.
Male and female pearl danios are similar in appearance. The biggest difference is that, when full of eggs, the female will have a more rounded body shape. It is not unusual for females to be more robust than the males, as the females are larger overall, and fuller-bodied. Males are smaller, slimmer, and more brightly colored. The males often show a red tint along the ventral aspect.
Breeding the Pearl Danio
Pearl danios are an easy-to-breed egg-laying fish. As with other danios, when breeding pairs form they are very loyal. The breeding tank should be warm, 79 to 86°F (26 to 30°C), and the water level kept shallow, about 4 to 6 inches (10 to 15 cm). Fine-leaved plants should be provided, either floating or planted in a group. Marbles make an excellent substrate that will allow stray eggs to fall out of the reach of hungry adult fish. A breeding grid or mop on the bottom would also suffice to protect eggs.
Pearl danios will spawn as pairs or in a school. Half as many females as males should be placed in the breeding tank several days before introducing the males. Once the males are added, pairs will form and leave the group to scatter eggs.
Spawning can also be initiated by adding a small amount of water every few hours so that the tank is gradually topped up; this simulates the rainy season of the natural habitat. Pairs will spawn the next morning. The easiest and quickest way to tell is to look at the female; if the fish have spawned she will be noticeably slimmer. Remove the adults as soon as spawning is completed, otherwise, they will consume their eggs.
Keep the tank dark while the eggs develop, to prevent fungal growth. The fry will emerge in 36 to 48 hours and should be fed freshly hatched brine shrimp or infusoria. Young danios grow rapidly and will be free-swimming in six to seven days. Fry may be raised on finely ground dry food or commercially prepared fry food.
More Pet Fish Species and Further Research
There are many danio species; each has a different color pattern and some (such as the giant danio) are much larger than others. Danios are all relatively easy to keep and are good company for your existing freshwater community of peaceful fish. If you’re interested in similar species, check out:
- Giant danio Species Profile
- Dwarf spotted danio Species Profile
- White cloud mountain minnow Species Profile
Check out additional fish breed profiles for more information on other freshwater fish.