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Max Size: 2.5cm

Dwarf Rasbora (Boraras maculatus)

The Dwarf Rasbora, also known as the Spotted Rasbora (Boraras maculatus), is a very peaceful species that are most suited to a nano or heavily planted aquarium. However, even though these fish are pretty small, they still require 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 more extensive shoals will not only result in a more colourful display but will make your fish feel more secure 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 small Rasboras, small Danios, Dwarf Barbs such as the Golden Dwarf Barb, 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 to provide plenty of shaded areas. The addition of dried leaf litter will further emphasise the natural feel and boost microbial 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 survive under these conditions, such as Microsorum, Java Moss, Anubias and 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.

The Dwarf Rasboras is closely related to several other species such as Chilli Rasbora, Phoenix Rasbora and the Exclamation Point Rasbora and can be somewhat challenging to differentiate to the untrained eye.

Tank Mates

1 ideal tank mate ideas for the Dwarf Rasbora include:

Ivantsoffs Blue Eye Rainbowfish(Pseudomugil ivantsoffi)
Quick Facts
Scientific NameBoraras maculatus
Year Described1904
Other NamesPygmy Rasbora, Spotted Rasbora, Three Spotted Dwarf Rasbora
ClassificationActinopterygii
OrderCypriniformes
FamilyCyprinidae
GenusBoraras
OriginsIndonesia, Malaysia, Singapore, Thailand
TemperamentPeaceful
Aquarium LevelMiddle - Top
DifficultyIntermediate
ShoalingYes
Best kept asGroups 8+
DietOmnivore
ReproductionEgg-Scatterer
Lifespan3 - 5 years
Water Parameters
Water TypeFreshwater
PH4.0 - 6.5
GH1 - 5
TDS18 - 90
Temperature
75 - 79℉
23.9 - 26.1℃

Photos

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

Videos

Dwarf Rasbora (Boraras maculatus) Rare Freshwater Nano Aquarium Fish Profile & Care

Natural Habitat

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

These fish are widely distributed in Malaysia, while the other countries have more limited populations. In addition, 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, it is believed the habitat of this species is endangered due to farming and human development.

Johor River

Feeding

Dwarf Rasboras are micro predators that feed on worms, small insects, crustaceans and other zooplankton in the wild. This species will accept good-quality dried foods of a suitable size; however, you should not feed them these exclusively. Instead, please 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 encourage them to come into breeding conditions.

Sexual Dimorphism

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.

Breeding

Like many Rasboras, The Dwarf Rasbora is an egg-scattering, non-stop spawner that does not display parental care. However, in the presence of both females and males, they can lay small numbers of eggs daily. In a well-planted, established aquarium, small numbers of fry may also begin to show up without human intervention.

If you want to raise higher numbers of fry, the fish will require a more controlled approach. You can still condition the adult group together but 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 implemented to achieve the same results.

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 suitable, they may initiate spawning 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. However, the parents should ideally only be kept in the breeding tank for a couple of days. You can expect the first eggs to begin hatching by the second day.

The tiny babies will survive on their yolk sacs for around 24 hours; after that, the fry 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 baby brine shrimp and microworm.

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

It would be best to wait a few weeks before making small water changes to avoid shocking the newly hatched fry unnecessarily.

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
Date Added: 11/10/2021 16:03:18 - Updated: 17/02/2022 17:02:43