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Maximum size : 10 cm

Simons Rasbora - Rasbora simonbirchi : Complete Fish Profile & Care Guide

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The exquisite Simon Rasbora (Rasbora simonbirchi) gracefully glides through the waters of a larger, well-appointed community aquarium, adding a sense of tranquillity and beauty to its surroundings. Renowned for their peaceful and adaptable nature, these Rasboras seamlessly integrate into a diverse array of aquatic ecosystems. With no specific water chemistry requirements, they harmoniously coexist with various popular fish species, allowing for endless possibilities when creating a vibrant community. Whether it's the elegant Livebearers, charismatic Tetras, captivating Gouramis, lively Rainbowfish, charismatic Catfish, or playful Loaches, the Simon Rasbora serves as a delightful companion to them all.

Designing an aquarium inspired by the native countries or river basins of the Simon Rasbora can be a fulfilling endeavour, immersing oneself in the captivating natural habitats these fish originate from. The sociable nature of these Rasboras calls for a group dynamic, where a gathering of at least six individuals creates a harmonious and captivating display. A larger assembly magnifies their vibrant colours, diminishes anxiety, and evokes authenticity within the aquatic environment.

Creating a captivating river tank manifold further enhances the natural allure of the Simon Rasbora's habitat. The careful arrangement of gravel, diverse-sized rocks, or smooth boulders as the substrate allows for the emulation of natural unidirectional flow. This simulated current transports one's imagination to the lush waterways that these Rasboras call home. Complementing this captivating landscape, the addition of aquatic plants and the artful placement of driftwood branches elevate the aesthetic appeal of the tank. In addition, hardy plant species such as Java fern, Bolbitis, and Anubias thrive in this environment, adding a touch of greenery and tranquillity.

While these Rasboras possess a remarkable beauty, it is important to note their acrobatic abilities as surface-dwelling jumpers. Their agility and penchant for exploration necessitate a tightly fitted aquarium lid to prevent any unexpected escapes. Admire the shimmering iridescence of the Simon Rasbora as it gracefully swims, showcasing an emerald green stripe that gracefully adorns its body, running from the posterior margin of its eye to the caudal fin. The striking appearance is further accentuated by crescent-shaped black marks along the posterior margins of the midlateral scales, culminating in a small black spot above the anal fin. Delicate and transparent fins, with a touch of reddish-orange, add the perfect finishing touch to this aquatic masterpiece.

Simons Rasbora Photos

Sexual Dimorphism

Distinguishing between male and female Simon Rasboras can be somewhat challenging. However, there are some characteristics that can provide clues. Sexually mature females tend to exhibit rounder bellies, and they are generally slightly larger in size compared to males. Additionally, females often display lighter colouration than their male counterparts. These subtle differences can assist in determining the sex of Simon Rasboras within a population.

Quick Facts

Scientific NameRasbora simonbirchi
Year Described2018
Other NamesNone
Max Size10 cm
Aquarium LevelMiddle - Top
Best kept asGroups 6+
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
PH6.0 - 7.5
GH2 - 12
73 - 79
22 - 26

Natural habitat

Simon Rasboras are native to the stunning middle Barito River Basin, located in the picturesque landscapes of Central Kalimantan in Borneo, Southeast Asia. These remarkable Rasboras are primarily found in the enchanting realm of blackwater rivers and streams, which meander through ancient forest peat swamps. As one immerses oneself in these pristine habitats, the water unveils a mesmerizing hue of brown, an enchanting testament to the infusion of tannins and other organic compounds derived from the decaying natural wonders surrounding them. The riverbeds, adorned with a tapestry of fallen leaves, branches, and twigs, create a stunning backdrop, while the gentle play of light filters through the protective canopy above, casting an alluring, subdued glow upon the aquatic realm. It is within this serene and evocative environment that Simon Rasboras thrive, embracing the softness and acidity of the water as they navigate their captivating existence.

How to breed the Simons Rasbora

Limited information is currently available on the breeding methods specific to Simon Rasboras. However, one can infer their potential reproductive behaviour by drawing upon knowledge of similar small Cyprinids. It is likely that these fish follow the pattern of being egg scatterers and constant spawners, exhibiting no parental care. In a well-established, densely planted aquarium, a small number of fry can appear naturally without any human intervention.

To increase the yield of fry, a more controlled approach is recommended. Conditioning the adult group together is a viable option, but it is crucial to establish a separate breeding tank. This tank should be dimly lit, and the bottom can be covered with mesh featuring appropriate-sized holes for eggs to fall through while preventing adult fish from accessing them. Alternatively, plastic grass matting, pebbles, or marbles can serve as suitable substrates. The water conditions in the breeding tank should ideally maintain a slightly acidic to neutral pH, with a temperature slightly higher than that of the general aquarium.

Initially, an internal power filter can be utilized and positioned to create a directed flow along the length of the tank. Once the adult fish are adequately conditioned, and the females display noticeable signs of being full of eggs, introducing one or two pairs into the breeding tank is advised. Spawning can be encouraged by gradually topping up the tank with small amounts of cooler water at regular intervals while providing multiple feedings of live and frozen foods throughout the day.

As adults tend to consume any eggs they encounter, removing them from the breeding tank after a couple of days is essential. At this stage, the power filter should be replaced with a sponge filter to prevent the unintentional suction of the developing fry. The incubation period of the eggs is influenced by temperature and typically ranges between 18 and 48 hours. Approximately 24 to 48 hours after hatching, the young will become free-swimming.

During the initial stages, providing the fry with Paramecium or infusoria as their primary food source is recommended. As they grow, introducing baby brine shrimp and microworms becomes suitable once the fry is sufficiently developed to accept them. Careful observation and regular monitoring of water quality are crucial to ensure the optimal growth and survival of the fry.

Diet & feeding

Simon Rasboras are known for their adaptable nature and are relatively undemanding when it comes to feeding. However, a diverse diet is highly recommended to ensure their optimal health and vitality. Alongside high-quality dried foods like flakes and granules suited to their size, incorporating regular servings of live, frozen, and freeze-dried delicacies such as bloodworms, tubifex, brine shrimp, and daphnia will provide them with a well-rounded nutritional intake. This balanced approach to feeding will contribute to the overall well-being and vibrancy of these fascinating Rasboras.

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