Rasbora cephalotaenia

Rasbora cephalotaenia

Rasbora cephalotaenia was first described by Pieter Bleeker in 1852. This fish belongs to the family Danionidae. The genus Rasbora is exceptionally species-rich with about 88 species.

The genus name Rasbora comes from the Indian language for a fish, also used in the Malay Peninsula. The species name cephalotaenia is derived from the Greek “kephalē” (head) and “tainía” (band), referring to the dark band that runs across the head of the fish.

Synonym: Leuciscus cephalotaenia.

Description

Appearance:
Rasbora cephalotaenia has a slender, elongated body with a distinctive dark lateral stripe running from the snout to the caudal fin. The head and flanks are silvery with a dark stripe, and the fins are usually transparent with a slight pinkish tinge. This fish can reach a length of 10 to 12 centimeters.

Differences between sexes:
Males are often smaller and more slender than females, which have a rounder belly, especially during the spawning season. There are no significant behavioral differences between the sexes.

Behavior and temperament:
Rasbora cephalotaenia is a peaceful and social fish that likes to swim in schools. They are not aggressive and can live well with other peaceful fish species. They usually swim in the middle waters of the aquarium.

Life Expectancy:
In the wild, these fish can live for 8 to 10 years, and in a well-maintained aquarium they can reach a similar age.

Blackwater Biotopes of Rasbora cephalotaenia

General Description of Blackwater Biotopes

Blackwater biotopes are unique aquatic environments characterized by their dark, tannin-rich waters. These waters get their color from the decomposition of organic matter such as leaves, branches, and other plant remains. The chemicals released during this process, such as tannins, give the water a brown-to-black color and make the water acidic (low pH).

Habitat and Environment

Rasbora cephalotaenia, also known as the Porthole Rasbora, is found in the blackwater habitats of Southeast Asia, particularly in the Malay Peninsula, Singapore, Sumatra and Borneo. These fish live mainly in slow-moving rivers and streams that flow through dense forests. The banks of these waters are often covered with trees and shrubs, which provide shade and contribute to the breakdown of organic matter in the water.

Water parameters

The waters in these biotopes are very soft (low hardness) and acidic, with a pH varying from 3.0 to 6.0. The water temperature is usually between 22°C and 28°C, which is ideal for the Rasbora cephalotaenia. The low hardness and acidic pH are crucial for the well-being of these fish, as they have adapted to these specific conditions.

Soil and Substrate

The bottom of blackwater biotopes usually consists of a mixture of sand and organic material, such as leaves and branches. This substrate provides a rich breeding ground for microorganisms, which in turn serve as a food source for the fish. The substrate is often covered with a layer of fallen leaves, contributing to the water’s dark color and the low pH value.

Vegetation

The vegetation in blackwater biotopes is usually dense and varied. Plants such as Microsorum pteropus (Java fern), Vesicularia dubyana (Java moss) and several species of Cryptocorynes are well adapted to the low light conditions and acidic waters. These plants provide hiding and breeding grounds for the fish and help maintain water quality by absorbing excess nutrients.

Natural Enemies and Food Chain

In their natural habitat, Rasbora cephalotaenia have to deal with various natural enemies, including larger predatory fish and birds. However, they are also small predators themselves, feeding on insects, worms and other small invertebrates. The presence of a rich microfauna in the substrate and vegetation provides a constant food source for these fish.

Seasonal Changes

Blackwater habitats can experience seasonal changes, such as flooding during the rainy season and droughts during the dry season. These changes can affect water quality and food availability, which in turn affects the population dynamics of the fish.

Blackwater biotopes are complex and dynamic ecosystems that provide unique habitats for species such as Rasbora cephalotaenia. The conservation of these biotopes is crucial for the survival of these and many other specialized species. The specific water parameters, rich vegetation and seasonal changes make these biotopes a fascinating subject of study and conservation.

Diet

In the wild:
Rasbora cephalotaenia feeds mainly on small insects, worms, crustaceans and other types of zooplankton.

In the aquarium:
In the aquarium, they can be fed with suitably sized dry food, but it is important to regularly offer small live or frozen food animals such as daphnia and artemia to maintain their best color and encourage reproduction.

The Aquarium

Aquarium size:
An aquarium of at least 100 centimeters in length is suitable for a small school of about eight of these fish. For a somewhat larger school, a larger aquarium of at least 150 centimeters is recommended.

Decoration:
The aquarium should be decorated with lots of plants and some rocks or pieces of wood to provide hiding places. A sandy bottom is ideal, but fine gravel can also be used.

Water parameters:
The best water parameters for Rasbora cephalotaenia are a temperature of 24-28°C, a pH of 6.0-7.5 and a hardness of 5-12 dGH.

Compatibility:
This species can live well with other peaceful fish such as tetras, guppies, and other small cyprinids.

Breeding aquarium and conditioning

Breeding Conditions:
For breeding, a separate breeding tank of about 40 liters is recommended with soft, acidic water (pH 6.0-6.5) and a temperature of 26-28°Celsius. Use a sponge filter to maintain water quality and provide dim lighting.

Conditioning:
Feed the fish live or frozen foods to get them in good condition for breeding. It is often useful to temporarily separate the males and females and then reunite them in the breeding tank.

The spawn

Colors and ritual:
During spawning, the colors of the fish become more intense. The mating ritual includes circling and vibrating of the fish. The eggs are usually laid on fine plants or moss. Spawning usually takes place in the morning.

Eggs:
The eggs are small and transparent, and a female can lay up to 200 eggs. The eggs are laid openly and unprotected by the parents.

Raising the fry

Hatching and Free Swimming:
The eggs hatch after about 24-36 hours, and the fry begin to swim freely after 3-4 days. There is no parental care, and the fry should be fed infusoria or liquid baby food until they are large enough to eat baby brine shrimp.

Particularities

Rasbora cephalotaenia is a fish that thrives in a well-planted aquarium with plenty of hiding places. They are sensitive to changes in water quality, so regular water changes are essential.

Conclusion

Rasbora cephalotaenia is a beautiful and peaceful fish that is suitable for both beginners and advanced aquarists. They require a well-planted tank and regular water changes to stay healthy. Their social nature makes them ideal for a community tank.

Keeping this species can be a rewarding experience, especially because of their interesting behavior and beautiful colors. They are relatively easy to breed under the right conditions, making them a good choice for hobbyists interested in breeding fish.

Author

John de Lange

Copyright images

Choy Heng Wah
Michael Lo – Junglemikey