Max Size: 2.5cm

Dwarf Rasbora (Boraras maculatus)

Dwarf Rasboras are a very peaceful species that are most suited to a nano or planted aquarium. However, even though these fish are pretty small, they still need a decent amount of swimming space.

Dwarf Rasboras are shoaling fish; therefore, it would be best to keep them in a group of at least eight individuals. Keeping this species in larger shoals will not only result in a more colourful display but will make your fish happier and more active.

Unfortunately, Dwarf Rasboras are not suitable for the typical community aquarium due to their very timid nature and small size. In addition, these fish are easily stressed if kept with most other species. They are, however, suitable for aquariums with other nervous and tiny fish species

such as other Dwarf Rasboras, small Danios, Dwarf Barbs, Pygmy Corydoras and smaller Loaches.

The ideal aquarium setup for these Dwarf Rasboras would contain a soft, sandy substrate and a few driftwood roots and branches, placed so that plenty of shaded areas are formed. The addition of dried leaf litter will further emphasise the natural feel and boost microbe colonies growth as decomposition occurs. You can leave the leaves in the aquarium to break down entirely, or you can remove them and replace them every few weeks.

It would be better to use fairly dim lighting to simulate the fish's natural habitat, adding aquatic plants that will be able to survive under such conditions; these can include Microsorum, Taxiphyllum or Cryptocoryne. Also, filtration does not need to be particularly strong as these fish mainly come from sluggish and still waters and may struggle if there is a fast current.

The overall body colour of Dwarf Rasboras is orangy-red. They possess a large dark spot on the side of their body, a small dark spot on the base of their caudal fin and a smaller dark spot at the bottom of the anal fin. In addition, their dorsal and anal fin has dark markings along the anterior edge highlighted with intense red on males. The size and shape of the dark marking at the base of the anal fin can be highly variable and may be represented by two distinct markings.

Quick Facts
Scientific NameBoraras maculatus
Other NamesPygmy Rasbora, Spotted Rasbora
OriginsIndonesia, Malaysia, Singapore, Thailand
Aquarium LevelMiddle - Top
Best kept asGroups 8+
Lifespan3 - 5 years
Water Parameters
Water TypeFreshwater
PH4.0 - 6.5
GH1 - 5
TDS18 - 90
75 - 79℉
23.9 - 26.1℃

Photos of Dwarf Rasboras

Dwarf Rasbora
Dwarf Rasbora
Dwarf Rasbora
Dwarf Rasbora
Dwarf Rasbora
Dwarf Rasbora
Dwarf Rasbora
Dwarf Rasbora
Dwarf Rasbora
Dwarf Rasbora

Natural Habitat

The Dwarf Rasboras are endemic to Thailand, Peninsular Malaysia and Singapore in South-Eastern Asia; however, there have been reports of this species being present in Borneo and Sumatra also.

These fish are widely distributed in Peninsular Malaysia, while the other countries have more limited populations. In addition, many populations from various countries have different patterns and colourations.

Dwarf Rasboras inhabit blackwater rivers and streams associated with peat swamps. They live amongst fallen leaves and branches in brownish water caused by the release of tannins. The water in these areas is usually really soft and acidic. In addition, these fish are often found in regions that have a low pH level. Unfortunately, the habitat of this species is endangered due to farming and human development.

Other Rasboras of interest

Black Line Rasbora(Rasbora borapetensis)
Chilli Rasbora(Boraras Brigittae)
Clown Rasbora(Rasbora kalochroma)
Emerald Eye Rasbora(Brevibora dorsiocellata)
Exclamation Point Rasbora(Boraras urophthalmoides)
Fire Rasbora(Rasboroides Vaterifloris)
View all Rasboras

What to feed the Dwarf Rasbora

Dwarf Rasboras are micro predators that feed on worms, small insects, crustaceans and other zooplankton in the wild. In the aquarium, this species will accept good-quality dried foods of a suitable size; however, you should not feed them these exclusively. Instead, also provide them with daily meals of small live and frozen foods such as artemia, daphnia and suchlike. This will bring out the best colouration of your fish and will also encourage them to come into breeding conditions.

How to Sex the Dwarf Rasbora

It is very straightforward to differentiate the males from female Dwarf Rasboras. The females have much rounder bellies and are typically larger than males. In contrast, males are slender and have more intense colouring than females, especially the dominant males.


How to Breed the Dwarf Rasbora

Like many Rasboras, The Dwarf Rasbora is an egg-scattering, non-stop spawner that exhibits zero parental care. However, in the presence of both females and males, they can lay small numbers of eggs daily. In a well-furnished, mature aquarium, small numbers of fry may also begin to show up without human intervention.

However, if you want to raise the number of fry, the fish will require a slightly more controlled approach. You can still condition the adult group together, but you should also set up a separate tank. This tank should be very dimly lit with the bottom either left bare or covered with some mesh with significant enough holes so that any eggs that fail to stick to the plants can pass through but small enough so that the adults cannot get to them. The broadly available artificial grass matting can also be used and works very well.

The water itself should be slightly acidic, and the temperature will need to be somewhat higher than usual. A good-sized clump of Java moss or other fine-leaved plants should also be placed in the tank taking up about half the available space. Filtration is unnecessary, but you can use a small, air-powered sponge filter if you like.

You should then introduce two or three pairs of well-conditioned adult fish into the tank. Again, it is sensible to make the transfer slowly to avoid extreme stress levels; however, if the water conditions are to their liking, they should begin to spawn the following morning.

While this species unquestionably consumes their eggs, they do not seem to seek them as other small cyprinids do actively.

Once spawning has begun, it should continue daily. The pairs should be kept in the tank for no more than a couple of days before removing them, as the first eggs should start to hatch by the second day after the original spawning.

The tiny babies will survive on their yolk sacs for around 24 hours or so, after which they will require infusoria, paramecium or other microscopic food. Then, about a week to 10 days later, the fry should be big enough to accept foods like nauplii, artemia and microworm.

As the days progress, the additional babies should start to appear from later spawning results.

It would be best to wait a week or two before performing small water changes to avoid shocking the young fry unnecessarily.

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Date Added: 11/10/2021 16:03:18 - Updated: 19/01/2022 14:13:33