Rasbora vulcanus
Rasbora vulcanus was first described by Heok Hui Tan in 1999. The genus name, Rasbora, is believed to be derived from the local Bengali name for the fish, Cyprinus rasbora, as mentioned by Hamilton in 1822. However, Bleeker designated R. cephalotaenia as the type species of the genus. The species name, vulcanus, refers to Vulcan, the Roman god of fire. This name highlights both the fish’s fiery red color and the volcanic environment of West Sumatra, where the species is found.
Synonym: Rasbora reticulata
Description
Rasbora vulcanus has a slender, elongated body that is laterally flattened. It features a terminal to superior mouth. The fins are translucent and match the color of the body, although the dorsal and anal fins have subtle dark borders. This species can grow to a maximum length of about 5 centimeters.
Sexual Dimorphism
Males are bright red, especially during the mating season. They are also slimmer than females. Females are lighter and show a breeding coloration where the front of their scales becomes black. They have a more robust body structure and are slightly larger than males.
Behavior and temperament
Rasbora vulcanus is a peaceful fish that thrives in schools of at least ten individuals. They are active and show their most vibrant colors when kept in groups.
These fish are peaceful and can live well with other peaceful fish species. They are not aggressive and do not show territorial behavior.
Rasbora vulcanus primarily swims in the middle layers of the aquarium and thrives in environments with plenty of hiding places and dim lighting. They are not shy and display their most vibrant colors when kept in a well-maintained aquarium.
Lifespan
There is no specific information about the lifespan of Rasbora vulcanus in the wild. In a well-maintained aquarium, Rasbora vulcanus can live up to 8 years.
Biotope
Rasbora vulcanus is native to Indonesia, specifically West Sumatra. These fish live in clear, fast-flowing coastal hill streams that flow into the Indian Ocean. They are found in small schools of about 30 fish. The rivers and streams where they occur include the Batang Si Joontour, Tripa Jaya, Kluet, and Alas rivers.
Natural Habitat
The natural habitat of Rasbora vulcanus includes clear, fast-flowing streams with rocky bottoms. These streams are typically surrounded by dense vegetation, which offers shaded areas in the water. There is abundant underwater plant life, including floating greenery and species such as Cryptocoryne wendtii, which provide hiding spots for the fish. The substrate of their habitat mainly consists of rocks and gravel, contributing to the water’s clarity and swift current.
Diet
In the wild, Rasbora vulcanus feeds primarily on small live food. Their diet includes water fleas, cyclops, and mosquito larvae. They are micropredators, meaning they feed on small invertebrates and other microorganisms found in their natural habitat.
In the aquarium, it is important to provide Rasbora vulcanus with a varied diet to enhance their health and coloration. Suitable food options include water fleas, cyclops, and both white and black mosquito larvae. Additionally, you can offer high-quality dry food, such as flakes or pellets specifically formulated for small tropical fish.
The Aquarium
A small school of Rasbora vulcanus, consisting of about 10 to 12 fish, requires an aquarium with a minimum volume of 80 liters and a length of at least 80 centimeters. If you plan to keep multiple pairs or a larger school, it is recommended to use an aquarium of 100 liters or more to ensure there is enough swimming space and territory for the fish.
Rasbora vulcanus likes a well-planted tank with lots of hiding places. Plants like Cryptocoryne are ideal as they provide shady spots for the fish to hide. Floating plants can also be added to soften the light and create a natural environment.
For an aquarium, using a dark substrate like fine gravel or sand is ideal, as it enhances the natural colors of the fish and creates a more natural appearance. Incorporating pieces of driftwood and rocks will provide additional hiding spots and further enhance the tank’s natural look.
Rasbora vulcanus thrives best in soft, slightly acidic water with the following parameters: temperature 24-26°Celsius and a pH of 6.0-7.0.
Suitable tankmates
Rasbora vulcanus is a peaceful fish that can live well with other peaceful species. Suitable tank mates include:
Other Rasbora species: such as Rasbora arundinata, Rasbora haru, Rasbora maninjau, and Rasbora bindumatoga.
Small tetras: such as neon tetras, cardinal tetras, and red-headed tetras.
Small bottom dwellers: such as Corydoras species and Otocinclus.
Other peaceful fish: such as guppies, platies, and small gouramis.
Breeding aquarium and conditioning
Rasbora vulcanus can be bred in both a standard aquarium and a specialized breeding tank. Breeding these fish is generally straightforward, as they typically lay eggs at a temperature of around 25°C. They are egg-laying species that deposit their eggs among the plants. Occasionally, you will discover small fish swimming among the plants.
If you choose to use a dedicated breeding tank, the following specifications are recommended. Use a breeding tank of approximately 20-40 litres. Ensure that the water is slightly acidic with a pH between 6.0 and 7.0 and a temperature between 24 and 26 °Celsius. Light the tank moderately to mimic a natural environment and to reduce stress to the fish. An air-driven sponge filter is ideal because it provides a gentle water flow and does not suck in young fish. Decorate the tank with plenty of fine-leaved plants such as Java moss. Place a few layers of marbles, pebbles, artificial grass or mesh on the bottom. The eggs will fall to the bottom and end up in a place where the parents can no longer eat them.
For breeding, it is important to condition the fish well with a varied diet. This can consist of live or frozen food such as white and black mosquito larvae, cyclops and the like.
The spawn
During the mating season, the colors of Rasbora vulcanus become more intense. The males show a bright red color, while the females develop a breeding coloration in which the front of their scales becomes black.
Mating usually takes place in the morning, especially when the morning sun lights up the aquarium. Rasbora vulcanus is a free-spreading fish. The eggs are spread out in the water and not protected in a cave or by mouthbrooding. The parents show little to no interest in the eggs after laying, which means that some of the eggs can survive without additional protection. In a specially set up breeding aquarium, the eggs fall down between the coarse substrate and are thus inaccessible to the parents who eat the eggs.
After laying eggs, remove the parents and place them back in their home aquarium.
Raising the young Rasbora vulcanus
Rasbora vulcanus eggs typically hatch within 24 to 48 hours, depending on the water temperature. After hatching, the fry begin to swim freely within one to two days. There is no parental care provided for Rasbora vulcanus; the parents show no interest in the eggs or the fry once they have been laid. Therefore, it is essential to remove the adult fish from the breeding tank after the eggs are laid to prevent them from eating the eggs or fry.
The fry are first fed with infusoria or liquid fry food. As they grow, they can also be fed microworms and freshly hatched artemia.
Conclusion
Rasbora vulcanus is a beautiful and gentle fish that flourishes in a well-planted aquarium with plenty of hiding spots and a dark substrate. They are relatively easy to care for and breed, and their vibrant colors make them a popular choice among aquarium enthusiasts. Suitable for both beginners and experienced aquarists, these fish can coexist well with other peaceful species.
Video
Author
John de Lange
Copyright images
Choy Heng Wah
