Symphysodon aequifasciatus – Blue Discus
Jacques Pellegrin first described the species Symphysodon aequifasciatus in 1904. These fish belong to the family Cichlidae and contain three recognized species. The genus name Symphysodon is derived from the Greek “symphysis” (joining) and “odious” (tooth), referring to the joined teeth. The species name Aequifasciatus means “evenly striped,” referring to the even stripes on the body. Their common names are Blue Discus or Green Discus.
Synonyms: Symphysodon discus var. aequifasciata, Symphysodon aequifasciatus aequifasciatus, Symphysodon aequifasciata haraldi, Symphysodon haraldi, Symphysodon aequifasciata axelrodi, Symphysodon axelrodi.
Description
The Blue Discus has a round, disc-shaped body shape. The head and flanks are usually blue-green with red stripes or dots. The fins are often translucent with a blue or red tint. These fish can grow up to 20 centimeters.
Differences between males and females:
Males tend to be slightly larger and have a more pointed dorsal fin, while females are rounder in shape. Behavioral differences are minimal, but males may display territorial behavior during the mating season.
Behavior and temperament:
Discus fish are generally peaceful and like to live in groups. They are not shy and usually swim in the middle waters of the aquarium.
Life expectancy:
In the wild, they can live up to 10 years, while in a well-maintained aquarium, they can live up to 15 years.
Difference between Symphysodon aequifasciatus and Symphysodon discus
The difference between Symphysodon aequifasciatus and Symphysodon discus lies mainly in their appearance and distribution:
Appearance
- Symphysodon aequifasciatus: Also known as the green or blue discus, this species often has a more pronounced pattern of stripes and spots. The colors range from green to blue with red accents.
- Symphysodon discus: Known as the red discus, this species has a more uniform red or brown color with less pronounced banding. The patterns are often more subtle than in S. aequifasciatus.
Distribution
- Symphysodon aequifasciatus: Mainly found in the western parts of the Amazon basin, such as the Rio Solimões and the Rio Putumayo.
- Symphysodon discus: This species is found in the eastern parts of the Amazon basin, especially in the Rio Negro and adjacent areas.
Behaviour and Habitat
Although both species exhibit similar behavior and live in similar habitats, slight differences in their water parameter preferences and social interactions may depend on their specific natural environment.
Although they are closely related and often kept together in aquariums, the differences in color and distribution are the main distinguishing features between these two species.
Biotope
Natural Habitat:
Discus fish are found in the Amazon Basin in countries such as Brazil, Peru, and Colombia. They live mainly in slow-moving rivers and streams such as the Rio Negro and the Rio Solimões.
Habitat features:
Their natural habitat has a lot of underwater vegetation, and the edges of the water are often covered with trees. The bottom usually consists of sand and leaves.
Climate:
They live in a tropical climate with seasonal flooding.
Diet
In the wild:
Discus fish primarily eat small invertebrates, insect larvae, and plant material.
In the aquarium:
They can be fed special discus food, frozen foods such as bloodworms, and occasionally vegetable food.
Do not feed:
Avoid feeding high-fat or highly processed foods.
The Aquarium
Aquarium size:
An aquarium of at least 150 centimeters is recommended for a small school. A larger aquarium is needed for a somewhat larger school.
Setup:
Fine sand should be used as a substrate, and lots of plants and hiding places should be provided. Rocks can also be added for extra structure.
Water parameters:
The ideal water parameters are a temperature of 26-30°C, pH of 6.0-7.0, and low hardness.
Compatibility:
Suitable tankmates include tetras, Corydoras, and other peaceful cichlids. Avoid aggressive or very active species.
Breeding aquarium and conditioning
Discus fish can be bred in a special breeding tank of about 100 liters. The water should be soft and acidic, with a temperature of 28-30°C. Use a sponge filter and provide dim lighting. Condition the fish with live food such as artemia. It is often useful to temporarily separate males and females and then reunite them for breeding.
The Spawn
During spawning, the discus fish’s colors become more intense. Courtship includes circling and vibrating. Eggs are often laid on a flat stone. Spawning usually takes place in the morning. About 100-200 bright and sticky eggs are laid.
Raising the fry
When discus fish prepare to hatch from eggs and develop skin secretions, they undergo some noticeable changes in color:
Color change
- Intensification of Colors: The colors of the parent fish often become more intense and vibrant. This may be an evolutionary adaptation to attract the attention of the fry and help them find their parents more easily.
- Darker Colors: Some discus can also become darker. This can help to increase the contrast between the parents and their surroundings, allowing the fry to track them better.
Function of Color Change
- Attracting Young: The more intense colors may help the young identify the parents and follow them for food.
- Communication: The color change may also be a form of communication between the parents and the young, and possibly even between the parents themselves.
These color changes are an important part of discus fish breeding behavior and contribute to the success of raising their young.
The eggs hatch after about 3 days. They then remain stuck in the place where they were laid as eggs. The young start to swim freely after 5-7 days. Both parents care for the young and guide them for about 2 weeks.
Skin secretion
The Blue Discus fry have a unique feeding pattern that sets them apart from many other fish species. After hatching from the eggs and swimming freely, the fry feed on a special skin secretion produced by the parents. This process occurs as follows:
- Production: Both parent fish develop a mucus layer on their skin that is rich in nutrients. This usually occurs shortly before the eggs hatch.
- Feeding: The young swim to the parents and feed by grazing on the skin secretions from their skin. These secretions contain essential nutrients that help the young grow and develop during the first few weeks of life.
Advantages
- Protection: This method of feeding keeps the young close to their parents, which protects them from potential predators.
- Nutritional Value: Skin secretion is highly nutritious and provides a complete diet for the young, which is crucial for their survival and growth in the early stages.
Behavior
- Parental care: Both parents are involved in caring for the young, taking turns feeding them. This behavior strengthens the bond between the parents and their offspring.
- Duration: The young usually remain dependent on the skin secretion for several weeks before they begin to feed independently.
This unique feeding method is a fascinating aspect of discus biology and contributes to their popularity among aquarium enthusiasts.
Particularities
Discus fish are sensitive to water quality and stress. They have complex social behavior and can form strong bonds with their tankmates.
Conclusion
Discus are beautiful and fascinating aquarium fish, but they require careful attention to water quality and environment. Due to their specific needs, they are not suitable for beginners. However, their social and peaceful nature makes them a valuable addition to a well-maintained aquarium.
Author
John de Lange
Copyright images
Suephoto.com (original website no longer online)
