Hyphessobrycon stegemanni (GÉRY, 1961) – Savanna Tetra

Etymology

The genus name Hyphessobrycon is a combination of two Ancient Greek words, “υπελάσσων” (hyphesson) and “βρύκον” (brycon). The word hyphesson means ‘of lesser stature’, and brycon is a generic name for a type of fish. Therefore, Hyphessobrycon means a small or lesser statured brycon.

The species name stegemanni was named in honor of Carlos Stegemann. He was a German baker and aquarist who lived in São Paulo, Brazil. Stegemann was a close friend of Harald Schultz (1909-1966), a renowned ichthyologist who collected the type series of Hyphessobrycon stegemanni.

The type series refers to the original specimens used to describe a new species. In the case of Hyphessobrycon stegemanni, Schultz collected the first specimens in the upper Rio Negro basin in Brazil in 1958. Dr. Jacques Géry later described the specimens as a new species by in 1961. Géry honored Stegemann by naming the new species after him.

Hyphessobrycon stegemanni is a member of the family Characidae. It is native to South America, specifically the upper Rio Negro basin in Brazil. This freshwater fish species is relatively small, reaching a maximum length of around 1.5 inches (4 cm). The Savanna Tetra has vibrant coloration, with silver-white on the lower half of its body and bright red on the upper half. Males have a more extended and pointed dorsal fin and more intense red coloration compared to females
In brief, the name Hyphessobrycon stegemanni is a combination of Greek and German words. They honor the features and collectors of this beautiful fish species. Its unique characteristics and interesting history make it a fascinating addition to any aquarium.

Classification

Hyphessobrycon stegemanni belongs to the order Characiformes. It is a diverse and widespread order of freshwater fish. The group appears throughout South and Central America, Africa, and Southeast Asia. This order includes well-known families of aquarium fish, such as the tetras, piranhas, and hatchetfish.

The family Characidae is one of the largest families of freshwater fish, consisting of over 2000 species. Characids have streamlined bodies, forked tails, and small adipose fins located between the dorsal fin and the tail. Many characids are popular aquarium fish due to their bright colors, active behaviors, and easy care requirements.

Hyphessobrycon stegemanni, commonly known as the Savanna Tetra, is a member of the characid family and is a popular choice among aquarists due to its vibrant coloration and active behavior. This species is relatively small, reaching a maximum length of around 1.5 inches (4 cm)

Distribution

Hyphessobrycon stegemanni is a freshwater fish species. The species is native to the middle Rio Tocantins basin in the states of Maranhão and Tocantins in central Brazil. It also appear in the principal affluent of the Rio Tocantins, the Rio Araguaia, in the states of Pará, Tocantins, and Mato Grosso.

Humans have recorded the majority of this species in the region east of the Tocantins main channel between Imperatriz and Palmas, upstream of both the river’s confluence with the Araguaia and the Tucuruí Dam. Although specimens from the Araguaia basin are rarer, there is at least one account of this species in the Ilha do Bananal area and another in the upper Rio das Mortes, near the municipality of Primavera do Leste in Mato Grosso.

The type locality of Hyphessobrycon stegemanni is between the Rio Manoel Alves Pequeno and Rio Vermelho in the Rio Tocantins basin, approximately 8°19’S, 47°25’W, municipality de Itacajá, Estado do Tocantins, Brazil. People also find it in Ilha do Bananal, approximately 11°S, 51°W, Rio Javaés, estado do Tocantins, Brazil.

On the whole, the range of Hyphessobrycon stegemanni is relatively limited to specific areas within the middle Rio Tocantins and Rio Araguaia basins in central Brazil. Understanding its natural habitat and range can help aquarists provide the best care for this species in captivity.

Habitat

Hyphessobrycon stegemanni is a freshwater fish. The species appears in range of almost entirely in the cerrado ecoregion of Brazil. This vast area of tropical wooded grassland is one of the most biodiverse savanna environments in the world. The area has high numbers of endemic fauna and flora. The cerrado ecoregion consists of forest savanna, wooded savanna, park savanna, gramineous-woody savanna, savanna wetlands, and gallery forests (closed canopy tall forest). The latter of which grows along the multitude of small streams that drain towards the Tocantins and Araguaia rivers.

The tributaries where humans can find Hyphessobrycon stegemanni are subject to fluctuations in discharge, with pronounced annual wet and dry seasons. These tributaries typically consist of a solid bedrock channel with additional substrate. The substrate can comprise variably-sized rocks, submerged tree roots, fallen branches, and leaf litter.

The increasing impact of dam construction and land clearing for the cultivation of soybean, cotton, corn, sugar cane, and pasture has drawn heavy international criticism. These activities are severe threats to river systems in the region, and habitat degradation is already widespread. More than half of the original cerrado vegetation has been destroyed due to human activities. It results in a decline in the biodiversity of the region. It also puts many species, including Hyphessobrycon stegemanni, at risk of extinction.

Understanding the habitat and range of Hyphessobrycon stegemanni can help in its conservation in the wild. The cerrado ecoregion is a crucial habitat for this species. And it is essential to address the impact of human activities to preserve the biodiversity of the region.

Maximum Standard Length

The maximum standard length of Hyphessobrycon stegemanni is typically between 25 and 35 mm, which makes it a relatively small species of tetra. However, what it lacks in size, it makes up for in its striking appearance and active behavior. The Savanna Tetra has vibrant coloration, which typically includes shades of blue, red, and gold. These colors are especially vivid in males during breeding season.

Despite its small size, Hyphessobrycon stegemanni is a highly social species. The fish prefers to be kept in groups of six or more in an aquarium setting. In addition to providing companionship, a larger group also helps to alleviate aggression within the school. A recommended aquarium size for a school of six to eight Savanna Tetras is at least 20 gallons.

When setting up an aquarium for Hyphessobrycon stegemanni, it is essential to provide a well-filtered environment with ample swimming space. As an active species, they benefit from a planted aquarium with open swimming areas.

While Hyphessobrycon stegemanni is a relatively small species of tetra, its appearence is vibrantly colored. It is quite active in behaviour. Keeping them in a school in a well-filtered and appropriately sized aquarium can provide a fascinating display for any aquarist.

Aquarium Size

To ensure the optimal health and well-being of Hyphessobrycon stegemanni in an aquarium setting, it is crucial to provide them with ample swimming space. The minimum recommended aquarium size for this active species is 60 x 30 cm or equivalent, although larger aquariums are strongly recommended, especially for larger schools of fish.

Larger aquariums provide more water volume, which results in more stable water conditions and helps dilute any waste produced by the fish. A larger surface area also supports the growth of beneficial bacteria, which aids in breaking down harmful compounds in the water.

In addition to providing adequate swimming space, a larger aquarium also makes maintenance easier for the aquarist. With a larger water volume, there are fewer chances of experiencing drastic changes in water quality, which means less frequent water changes and more time to enjoy the beauty of the fish.

Therefore, when considering an aquarium for Hyphessobrycon stegemanni, it is important to prioritize providing ample swimming space and use a larger aquarium with a minimum base dimension of 60 x 30 cm or equivalent to ensure stable water conditions and support the fish’s overall health and well-being.

Maintenance

An aquarium arrangement that features a sandy substrate, driftwood roots and branches, or a heavily planted set-up is perhaps the best option for showcasing the natural beauty of Hyphessobrycon stegemanni. The addition of dried leaf litter can further enhance the natural feel of the aquarium and offer additional cover for the fish. As the leaves decompose, microbe colonies grow, providing an additional food source for both adults and fry.

The humic substances released by the decaying leaves are also beneficial to the overall health of the aquarium. They help to lower the pH of the water, which can be helpful for other fish species that prefer slightly acidic conditions. Additionally, the antibacterial properties of humic substances can help prevent disease in the aquarium.

When it comes to plant choices, Hyphessobrycon stegemanni thrives in heavily planted aquariums. Options such as Amazon sword plants, Java fern, and Anubias can be included in the aquarium to provide visual interest, hiding spots, and breeding areas for the fish.

A well-planted aquarium with a sandy substrate, driftwood roots and branches, and dried leaf litter can provide a natural and stimulating environment for Hyphessobrycon stegemanni. The addition of live plants and natural elements not only creates a beautiful aquascape but also contributes to the overall health and well-being of the fish.

Water Conditions

Maintaining proper water parameters is crucial for the health and well-being of Hyphessobrycon stegemanni. People should maintain the water temperature range for this species between 20 and 25°C, which may require a heater in cooler environments.

Hyphessobrycon stegemanni prefers slightly acidic to neutral water conditions, with a pH range between 5.5 and 7.5. Regular monitoring of pH levels is important. People should make adjustment when necessary to ensure that the fish are thriving in their environment.

Water hardness refers to the concentration of dissolved minerals such as calcium and magnesium in the water. People should keep this parameter within a range of 36-215 ppm. People can use test kits to determine the hardness of the aquarium water, and make appropriate adjustments to ensure optimal water conditions for the fish.

To maintain these water parameters, it is recommended to use a reliable thermometer and pH and hardness test kits. Water temperature can be adjusted using a heater, while pH and hardness can be adjusted using various methods, such as buffers or mineral additives. Sudden and drastic changes to water parameters can be stressful for the fish and may lead to health problems. Therefore, people should make gradual adjustments over a period of several days or weeks, depending on the severity of the issue.

Regular water changes are also essential for maintaining good water quality and diluting any harmful compounds that may have accumulated in the aquarium. Weekly water changes of 25% or more are recommended.

Proper maintenance of water parameters is essential for the health and well-being of Hyphessobrycon stegemanni. Keeping the water temperature between 20 and 25°C, pH between 5.5 and 7.5, and hardness between 36 and 215 ppm can help ensure that the fish thrive in their environment. Regular monitoring and adjustments to water parameters are necessary to maintain a stable and healthy aquarium for this species.

Diet

Hyphessobrycon stegemanni is an omnivorous species that feeds on a variety of food sources in the wild, including small invertebrates, crustaceans, filamentous algae, fallen fruit, and similar items.

In the aquarium setting, this species can survive on a diet of dried foods. However, to ensure optimal health and well-being, it is best to offer a varied menu that includes live and frozen chironomid larvae (bloodworm), mosquito larvae, Daphnia, Moina, and other similar foods.

Overfeeding can lead to poor water quality and health problems for the fish. Therefore, it is recommended to feed small amounts several times a day, rather than one large meal, and to monitor the fish’s behavior and appearance regularly to ensure that they are healthy and thriving.

In conclusion, offering a varied diet that includes live and frozen foods is important for the optimal health and well-being of Hyphessobrycon stegemanni in the aquarium setting. Overfeeding should be avoided, and regular monitoring of the fish’s behavior and appearance is necessary to maintain a healthy and thriving aquatic environment.

Behaviour and Compatibility

Hyphessobrycon stegemanni is a very peaceful species, making it an ideal resident of a well-researched community aquarium. This species is best-maintained alongside similarly-sized characids, gasteropelecids, lebiasinids, smaller callichthyid or loricariid catfishes, and non-predatory, small-to-medium-sized cichlids.

When keeping this species, it is recommended to buy a mixed-sex group of at least 8-10 specimens. Including other schooling fish can provide a sense of security for the group and create a more natural-looking spectacle in the aquarium.

It should be noted that larger, more aggressive fish should be avoided as they may harm or intimidate Hyphessobrycon stegemanni. Additionally, any fish that could fit in the mouth of this species should be avoided.

Creating a well-planted aquarium with hiding places and open swimming areas is ideal for this species. It is also important to maintain good water quality and provide a balanced diet to ensure optimal health and well-being.

On the whole, Hyphessobrycon stegemanni is a very peaceful species that is ideal for a well-researched community aquarium. It should be kept with similarly-sized, non-aggressive fish and in a well-planted aquarium with hiding places and open swimming areas. Regular monitoring of water quality and a balanced diet can help ensure optimal health and well-being for this species.

Sexual Dimorphism

Distinguishing sexually mature female Hyphessobrycon stegemanni from males can be done based on their deeper body and slightly larger size. This difference becomes more noticeable as the fish reach full maturity, making it helpful for breeding purposes.

In addition to physical differences, males may display more intense coloration and fin displays during courtship and breeding behaviors. To encourage successful spawning, appropriate breeding conditions and a suitable breeding pair should be provided.

Regular monitoring of the fish’s behavior and appearance is crucial to identify potential health issues or stressors in the aquarium. Maintaining a stable and healthy aquarium environment is recommended to support optimal health and well-being for all fish, including Hyphessobrycon stegemanni.

In summary, Hyphessobrycon stegemanni females can be distinguished from males based on their deeper body and slightly larger size, while males may display more intense coloration and fin displays during breeding behaviors. Regular monitoring and maintaining a stable aquarium environment are essential for the species’ overall health and well-being.

Reproduction

There is currently no available information regarding the reproductive behavior of Hyphessobrycon stegemanni.

Notes

In the aquarium hobby, the name Hyphessobrycon stegemanni has often been misapplied to Hemigrammus ataktos Marinho, Dagosta, & Birindelli 2014 because they both have a dark lateral stripe on the body and occur together in the rio Tocantins system. However, there are distinct differences between the two species, such as the dorsal and anal fins not being elongated in adult males and inner premaxillary teeth having 7-9 cusps. H. stegemanni also has scales on the caudal-fin restricted to the base.

H. stegemanni belongs to the putative ‘H. heterorhabdus-group’ of closely-related species within the genus, which is characterized by a ‘longitudinal pattern’ consisting of a thin, usually dark, lateral body stripe. Lima et al. (2014) proposed a putatively monophyletic H. heterorhabdus-group containing three species that all possess a well-defined, elongate humeral blotch, a dark, well-defined midlateral stripe that becomes blurred towards the caudal peduncle, a longitudinal red stripe extending along the body above the midlateral line, and the upper half of the eye red. However, H. stegemanni and other species in Géry’s H. heterorhabdus group have a continuous, solid dark lateral stripe on the body and no obvious humeral blotch.

Hyphessobrycon was originally created by Durbin in Eigenmann (1908) as a subgenus of Hemigrammus, with the absence of scales on the caudal-fin distinguishing the two. Eigenmann (1918, 1921) also revised the grouping, while Géry (1977) created artificial groups of species based on color pattern, which continue to be redefined.

Weitzman & Palmer (1997) hypothesized the existence of a monophyletic assemblage within the genus based on color pattern and male fin morphology, known as the ‘rosy tetra clade,’ with the presence of a prominent dark marking on the dorsal-fin supporting its monophyly. Some authors consider this assemblage, plus other morphologically similar species, to represent Hyphessobrycon sensu stricto, while the remaining species are included in a much-expanded H. heterohabdus group.

Malabarba et al. (2012) revalidated the genus Ectrepopterus Fowler, which was previously considered a synonym of Hyphessobrycon. They analyzed its relationships within the Characidae in the context of Mirande’s (2010) previous work, including the type species, H. compressus, for the first time in such a study. The results showed that H. compressus is more closely related to ‘rosy tetra’ representatives, such as H. eques, H. pulchripinnis, and H. socolofi, than other members of the genus, including H. anisitsi, H. bifasciatus, H. elachys, H. herbertaxelrodi, and H. luetkeni.

References

1. Géry, J. , 1961 – Tropical Fish Hobbyist 9(9): 7-13
   The Savannah tetra: Hyphessobrycon stegemanni sp. nov.
2. Calcagnotto, D., S. A. Schaefer, and R. DeSalle, 2005 – Molecular Phylogenetics and Evolution 36(1): 135-153
   Relationships among characiform fishes inferred from analysis of nuclear and mitochondrial gene sequences.
3. Géry, J., 1977 – T. F. H. Publications, Inc.: 1-672
   Characoids of the world.
4. Lima, F. C. T., D. P. Coutinho and W. B. Wosiacki, 2014 – Zootaxa 3872(2): 167-179
   A new Hyphessobrycon (Ostariophysi: Characiformes: Characidae) from the middle Amazon basin, Brazil.
5. Malabarba, L. R., V. A. Bertaco, F. R. Carvalho & T. O. Litz., 2012 – Zootaxa 3204: 47-60
   Revalidation of the genus Ectrepopterus Fowler (Teleostei: Characiformes), with the redescription of its type species, E. uruguayensis.
6. Marinho, M. M. F., F. C. P. Dagosta and J. L. O. Birindelli, 2014 – Neotropical Ichthyology 12(2): 257-264
   Hemigrammus ataktos: a new species from the rio Tocantins basin, central Brazil (Characiformes: Characidae).
7. Mirande, J. M., 2010 – Neotropical Ichthyology 8(3): 385-568
   Phylogeny of the family Characidae (Teleostei: Characiformes): from characters to taxonomy.
8. Oliveira, C. A., G. S. Avellino, K. T. Abe, T. C. Mariguela, R. C. Benine, G. Orti, R. P. Vari, and R. M. Corrêa e Castro, 2011 – BMC Evolutionary Biology 11(1): 275-300
   Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling.
9. Reis, R. E., S. O. Kullander and C. J. Ferraris, Jr. (eds), 2003 – EDIPUCRS, Porto Alegre: i-xi + 1-729
   Check list of the freshwater fishes of South and Central America. CLOFFSCA.
10. Weitzman, S. H. and L. Palmer, 1997 – Ichthyological Exploration of Freshwaters 7(3): 209-242
    A new species of Hyphessobrycon (Teleostei: Characidae) from the Neblina region of Venezuela and Brazil, with comments on the putative `rosy tetra clade’.
11. Zarske, A., 2014 – Vertebrate Zoology 64(2): 139-167
    Zur Systematik einiger Blutsalmler oder “Rosy Tetras” (Teleostei: Ostariophysi: Characidae).