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Maximum size : 4 cm

Volcano Rasbora - Rasbora vulcanus : Complete Fish Profile & Care Guide

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Volcano Rasboras (Rasbora vulcanus) are esteemed for their active nature, peaceful disposition, aesthetic appeal, and ease of care, making them a highly desirable addition to any community aquarium. However, it is important to note that Volcano Rasboras naturally thrive in schools, therefore, it is advisable to maintain them in groups consisting of a minimum of eight individuals. Not only will keeping them in larger numbers alleviate their unease, but it will also result in a more authentic and captivating display. In a group setting, the males will exhibit their most vibrant colours as they compete for female attention.

Volcano Rasboras do not possess specific requirements regarding water chemistry, allowing for compatibility with a wide range of popular fish commonly found in the hobby. Suitable tankmates may include small Cyprinids such as Barbs, as well as Tetras, Rainbowfish, Livebearers, Catfish, and Loaches. While the choice of decor is not critical, it has been observed that these Rasboras display enhanced colouration when housed in heavily planted setups featuring a dark substrate. Adding driftwood roots or branches, along with some floating plants to provide diffused lighting, is appreciated and contributes to a more natural ambience.

It is important to note that introducing Volcano Rasboras to an immature aquarium with unstable water chemistry should be avoided, as they may be vulnerable to fluctuations. Furthermore, ensuring a secure enclosure with a tightly-fitting lid or a reduced waterline is crucial, as these agile fish are prone to jumping when startled or excited.

Volcano Rasboras exhibit a distinct dark lateral line running along the entire length of their bodies, accompanied by fins displaying a pinkish-red hue. In addition, their sides are adorned with a reticular scale pattern resembling that of Barbs. The males showcase a reddish-orange tone across their bodies, which intensifies during spawning, while mature females exhibit a pale golden hue throughout their bodies.

Volcano Rasbora Photos

Sexual Dimorphism

Distinguishing between male and female Volcano Rasboras can be accomplished with relative ease. Males typically exhibit a leaner physique, slightly smaller size, and a more vivid colouration in comparison to their female counterparts. Conversely, mature females tend to possess a more robust body structure, slightly larger size, and a significantly less vibrant appearance when compared to males.

Quick Facts

Scientific NameRasbora vulcanus
Year Described1999
Other NamesNone
Max Size4 cm
Aquarium LevelBottom - Middle
DifficultyBeginner - Intermediate
Best kept asGroups 8+
LifespanUp to 8 Years

Water Parameters

Water TypeFreshwater
PH6.5 - 7.5
GH2 - 15
73 - 79
22 - 26

Natural habitat

At present, there exists a limited corpus of information regarding the precise origins of Volcano Rasboras. However, prevailing knowledge suggests their endemism to the Batang River, located in the northern region of West Sumatra, Indonesia, within the expansive domain of Southeast Asia. These fish inhabit crystalline, moderately flowing streams within this habitat, displaying an affinity for such environments.

How to breed the Volcano Rasbora

Volcano Rasboras exhibit an intriguing reproductive behaviour as egg-scattering, continuous spawners devoid of parental care. However, under favourable conditions, well-fed individuals tend to engage in spawning activities, leading to the emergence of a modest number of fry. In a densely planted community aquarium, these fry can survive. To optimize fry production, the utilization of a separate breeding tank is essential. This designated tank should possess specific characteristics, such as a relatively shallow depth, subdued lighting, and an abundance of fine-leaved plants.

An alternative approach involves covering the tank's base with mesh, marbles, or pebbles to facilitate the descent of non-adhesive eggs, preventing the adults from accessing them. Maintaining a slightly acidic water environment in the breeding tank is crucial, and employing a mature air-powered sponge filter aids in efficient filtration. Moreover, raising the temperature slightly above the customary level in the main aquarium can be beneficial. Small amounts of cold water can be intermittently added to the tank to stimulate spawning, simulating rainfall. Conditioning the fish with a generous supply of live and frozen foods further promotes the spawning process.

Once the spawning phase concludes, it is imperative to promptly remove the adult fish, as they pose a threat to both eggs and fry. The incubation period of the eggs varies with temperature, typically hatching within a span of 24 to 48 hours. Subsequently, after one to two days, the fry gains the ability to swim independently. Initially, feeding the newly hatched fry with infusoria or commercially available liquid fry food is recommended. As the fry grows in size, the introduction of microworms and baby brine shrimp into their diet becomes appropriate.

Diet & feeding

In their natural habitat, Volcano Rasboras assume the role of micro predators, primarily nourishing themselves with minuscule invertebrates, notably insect larvae. Nevertheless, these fish demonstrate a versatile feeding behaviour within an aquarium setting, readily accepting a wide range of premium dry foods. However, it is crucial to supplement their diet with a diverse array of nourishment, incorporating live, frozen, or freeze-dried options of appropriate size. By providing this varied dietary approach, the nutritional needs of Volcano Rasboras can be effectively met.

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