Blue Line Rasbora - Rasbora sarawakensis : Complete Fish Profile & Care Guide
Table of contents
Introduction
The Blue Line Rasbora (Rasbora sarawakensis), while not commonly found in the aquarium trade, possesses an appealing combination of sociability and aesthetic charm. This species seamlessly integrates into peaceful communities of Southeast Asian or Indian fish species such as Rasboras, Barbs, Loaches, and Gouramis. To promote a harmonious environment, a group of at least eight to ten Blue Line Rasboras is recommended, as they naturally exhibit schooling behaviour. Maintaining them in sufficient numbers enhances their confidence and allows for a more visually captivating and natural display. During mating competitions, males exhibit their most vibrant colours as they vie for female attention.
To optimize the colouration of Rasboras, it is advisable to house them in a well-planted tank with a dark substrate, although the choice of decor is not of utmost importance. Including floating plants and driftwood roots or branches adds a touch of natural authenticity to the aquarium, further enhancing the overall aesthetics. As Blue Line Rasboras inhabit sluggish waters in their natural habitat, the filtration system does not require excessive strength.
Characterized by a relatively stout body and a prominent, pointed head, the Blue Line Rasbora can be distinguished from other species by its golden ground colour and distinctive orange longitudinal stripe.
Blue Line Rasbora Photos
Sexual Dimorphism
Distinguishing between male and female Blue Line Rasboras (Rasbora sarawakensis) is a straightforward task. Females typically exhibit less vibrant colouration, possess a larger overall size, and appear plumper compared to males. In contrast, the males showcase a slimmer physique, smaller body size, and more vivid colours in comparison to their female counterparts.
Quick Facts
| Scientific Name | Rasbora sarawakensis |
|---|---|
| Year Described | 1951 |
| Other Names | Sarawak Rasbora |
| Kingdom | Animalia |
| Classification | Actinopterygii |
| Order | Cypriniformes |
| Family | Cyprinidae |
| Genus | Rasbora |
| Origins | Indonesia |
| Max Size | 5 cm |
| Temperament | Peaceful |
| Aquarium Level | Middle - Top |
| Difficulty | Beginner - Intermediate |
| Shoaling | Yes |
| Best kept as | Groups 10+ |
| Diet & Feeding | Omnivore |
| Reproduction | Egg-Scatterer |
| Average Lifespan | Up to 5 Years |
Water Parameters
| Water Type | Freshwater |
|---|---|
| pH | 6.0 - 7.5 |
| GH | 2 - 12 |
| ℉ | 72 - 78 |
|---|---|
| ℃ | 22 - 25 |
Natural Habitat
The Blue Line Rasbora is found in both the Malaysian state of Sarawak and the Indonesian province of Kalimantan Barat. Numerous river systems within these regions serve as their natural habitats, including Batang Kayan, Sungai Sarawak, and Mempawah. Typically seeking shelter beneath the canopy of the rainforest, these Rasboras inhabit sluggish-flowing streams adorned with dense emergent vegetation. The streambeds are often covered with silt and fallen tree limbs, contributing to a thick layer of sediment. Despite this, the water in their native habitats tends to maintain relative clarity. As organic matter decomposes within the stream, it releases tannins, resulting in a pale brown hue that characterizes the water in these environments.
Breeding
The successful breeding of Blue Line Rasboras (Rasbora sarawakensis) in the aquarium hobby remains uncertain, although it is deemed feasible. These Rasboras are characterized as continuous spawners, scattering their eggs without exhibiting parental care towards the offspring. However, under favourable conditions, such as a healthy adult group and a well-established, densely-planted aquarium, small numbers of fry may emerge naturally without human intervention. If a higher yield of fry is desired, a more controlled approach is recommended.
To enhance the chances of successful breeding, one or more dedicated containers should be prepared, filled halfway with water, and maintained under dim lighting conditions. The container's bottom should be covered with mesh or artificial grass matting, allowing the eggs to pass through while preventing adult fish from accessing them. The water in the container should possess a slightly acidic to neutral pH, along with a gentle temperature increase. Power filters can be incorporated into the aquarium setup, with the flow directed along its length. Introducing one or two pairs of well-conditioned adult fish to each container, particularly when the females appear full of eggs, can help initiate spawning. Gradually replenishing the aquarium with cooler water and providing small amounts of live and frozen foods contribute to stimulating the spawning process. It is common for a female to spawn multiple times before depleting her supply of eggs.
To safeguard the fry from being drawn into the power filter, replacing it with a mature sponge filter after a couple of days is advisable. Incubation of the eggs generally takes between 18 to 48 hours, with the young becoming free-swimming within 24 to 48 hours after hatching. Initially, the fry should be fed Paramecium or similar microorganisms, progressing to microworms and brine shrimp once they have reached a suitable size to accept these food sources.
Diet & Feeding
Within the confines of a home aquarium, the Blue Line Rasbora readily accepts various high-quality dried food options, including granules, flakes, and sinking pellets. These modern food products have been specifically formulated to fulfil the essential nutritional requirements necessary for maintaining the health and well-being of your fish. Supplementing their diet with occasional offerings of live, frozen, or freeze-dried meals such as bloodworm, daphnia, and tubifex once or twice a week can provide additional health benefits and contribute to the overall well-being of your fish, although it is not mandatory.
It is important to note that bloodworms should be provided sparingly, serving as an occasional treat rather than a staple diet, as they can pose challenges for digestion and potentially lead to blockages. As an omnivorous species in the wild, the Blue Line Rasbora naturally incorporates some vegetable matter into its diet. While most modern fish foods already account for this and include vegetable components, supplementing their diet with blanched vegetables such as spinach, broccoli, and zucchini can further enhance their nutritional intake. Care should be taken to avoid overfeeding, and any uneaten food should be promptly removed the following day to maintain water quality and prevent waste accumulation.
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