Boulengerella maculata (Valenciennes, 1850)

Synonyms

Xiphostoma maculatum Valenciennes, 1850 and Xiphostoma taedo Cope, 1872.

Etymology

The genus Boulengerella is named after the Belgian-British zoologist George Albert Boulenger (1858-1937). The species name maculata comes from the Latin word “maculata”, meaning “spotted”, in reference to the species’ distinctive spotted color pattern.

Classification

Ctenoluciidae.

Distribution

The type locality of this species is listed as the ‘Amazon River, Brazil’, but it is now known to be distributed across a much wider area that includes the Amazon, Orinoco, and Tocantins river systems. This species has been recorded in various regions including Ecuador, Colombia, Peru, Brazil, and Venezuela.

There are some distinct differences in populations of this species from different regions. For example, populations from Peru, the Leticia area of Colombia, and the Rio Javari basin in Brazil have been found to have different numbers of vertebrae and pored lateral line scales compared to those from the lower Amazon and Rio Orinoco.

Amazon

The Amazon, also known as the Amazon River, is one of the most extensive and biodiverse river systems on the planet. The river spans approximately 4,000 miles (6,400 km) from its source high up in the Andes Mountains of Peru to its mouth in the Atlantic Ocean, crossing through several countries including Brazil, Colombia, and Peru.

The Amazon River basin is home to the world’s largest tropical rainforest, which is a crucial component of the planet’s ecosystem. This region contains a wide range of plant and animal species, many of which are unique to the area. The Amazon rainforest is also a significant carbon sink, helping to regulate the Earth’s climate.

The Amazon River itself is the largest river in the world by volume and has over 1,100 tributaries. Its flow of water is so extensive that it accounts for nearly one-fifth of all the freshwater that flows into the world’s oceans.

The river is home to numerous species of fish, including the famous Arapaima, which can grow up to 9 feet (2.7 meters) long and weigh over 400 pounds (180 kg). Other species that are found in the river include the popular game fish, Peacock Bass, as well as catfish, piranhas, and stingrays.

The Amazon River is also home to a wide range of mammals, including jaguars, river otters, and capybaras, which is the largest rodent in the world. The river and its surrounding forests also provide habitat for over 400 species of birds, including the colorful macaws, parrots, and toucans.

Despite the importance of the Amazon River and its surrounding rainforest, this ecosystem is under threat from deforestation, pollution, and climate change. Deforestation, primarily caused by logging and farming activities, has led to significant habitat loss for many species, as well as increased greenhouse gas emissions.

The river and its surrounding communities are also at risk from pollution, primarily caused by mining activities, oil spills, and agricultural runoff. Climate change is also impacting the Amazon region, causing shifts in weather patterns, increased droughts, and more frequent and severe flooding.

Efforts are being made to protect the Amazon River and its surrounding rainforest, including increased conservation efforts, sustainable farming practices, and the promotion of ecotourism. These efforts are vital to protect the unique and biodiverse ecosystem of the Amazon River and ensure that it continues to thrive for generations to come.

Boulengerella maculata (Valenciennes, 1850)

Despite these differences, this species is generally well adapted to life in freshwater environments and can be found in a variety of habitats including main river channels, tributaries, and floodplain lakes. They are known to feed primarily on smaller fish and insects, but can also adapt to a variety of other food sources in captivity.

In the wild, this species plays an important role in the aquatic ecosystem as both predator and prey. They are preyed upon by larger fish and birds, while also feeding on a variety of small insects and crustaceans.

When kept in captivity, it is important to provide this species with a well-maintained aquarium that mimics their natural environment. This may include plants, hiding places, and moderate water flow. They prefer slightly acidic to neutral water with a temperature range of 73-81°F (23-27°C). They are generally peaceful and can be kept with other peaceful species, but may become aggressive towards their own kind if not kept in groups.

Habitat

This particular species is known to be pelagic and tends to be found in flowing stretches of main river channels and larger tributaries of both white and black water rivers, as well as in floodplain lakes, especially during its adult stage.

Maximum Standard Length

The largest specimen of this species that has been officially recorded measured 329 mm in length.

Aquarium Size

It is recommended to use an aquarium with base dimensions of 240 x 90 cm or larger.

Maintenance

Although relatively undemanding, this species appreciates some surface cover in the form of floating or overhanging vegetation or branches. It thrives in water with a high proportion of dissolved oxygen and a moderate degree of water movement, so external filters, powerheads, airstones, and other equipment should be used as needed.

Because stable water conditions are crucial to its well-being, this fish should never be introduced into biologically immature aquariums. Weekly water changes of 30-50% of the aquarium volume should be considered mandatory.

Since Boulengerella species are known to be prodigious jumpers, it is essential to use a tightly-fitting cover on the aquarium. It may also be beneficial to cover the back and sides of the aquarium to reduce the likelihood of the fish swimming into the glass, especially in confined surroundings where it can be skittish.

Water Conditions

Temperature: 22 – 28 °C
pH: 5.0 – 7.5
Hardness: 18 – 215 ppm

Diet

This species is an obligate predator in the wild and feeds mainly on smaller fishes and insects. However, in captivity, it can adapt well to dead alternatives. Smaller specimens can be offered bloodworm, small earthworms, chopped prawn, and similar foods, while adults will accept strips of fish flesh, whole prawns/shrimp, mussels, live river shrimp, and larger earthworms.

Insects such as crickets are also suitable to feed, but it’s best to fill their stomachs by feeding them fish flakes or some type of vegetable matter before offering them to the fish.

As with most predatory fish, this species should not be fed mammalian or avian meat, such as beef heart or chicken. Some of the lipids contained in these foods cannot be properly metabolized by the fish and can lead to excess fat deposits and even organ degeneration.

Similarly, there is no benefit to using “feeder” fish, such as livebearers or small goldfish. These fish can introduce parasites or diseases to the aquarium, and they tend not to have high nutritional value unless they are properly conditioned beforehand.

Behaviour and Compatibility

Peaceful with anything too large to swallow and can be maintained in a community provided tankmates are chosen with care.

It’s recommended to avoid adding aggressively territorial or very competitive species to the tank with this fish. Instead, the best tankmates are similarly-sized, peaceful fishes such as Geophagus or Acestrorhynchus species and many doradid or loricariid catfishes.

Geophagus species

Geophagus is a genus of freshwater cichlids that is native to South America. These fish are known for their attractive colors and patterns, as well as their peaceful nature, which makes them popular among aquarists. In this article, we will discuss the characteristics, habitat, and care requirements of Geophagus species.

Characteristics

Geophagus species are relatively large cichlids that can grow up to 10-12 inches in length, depending on the species. They have a disc-shaped body with a sloping forehead and a mouth that is slightly underslung. The fins of these fish are generally large and rounded, with the dorsal and anal fins extending back towards the caudal fin.

One of the most distinctive features of Geophagus species is their coloration. These fish come in a wide range of colors, including shades of red, orange, yellow, blue, green, and black. They also have intricate patterns on their bodies, which can range from spots and stripes to more complex designs.

Habitat

Geophagus species are native to the rivers, streams, and lakes of South America, where they can be found in a variety of different habitats. Some species are found in clear, fast-moving rivers, while others prefer slower-moving waters with muddy bottoms. Most Geophagus species are also found in areas with dense vegetation, rocks, or logs, which provide them with cover and shelter.

Care Requirements

Geophagus species are relatively easy to care for and make great additions to a community aquarium. They are peaceful fish that can be kept with other non-aggressive species of similar size. However, they should not be kept with smaller fish, as they may view them as food.

In terms of aquarium requirements, Geophagus species prefer a spacious tank with plenty of hiding places, such as rocks, driftwood, and plants. They also prefer a sandy substrate, as they like to sift through the sand in search of food.

Water conditions are also important for Geophagus species. These fish prefer soft, slightly acidic water with a pH of around 6.5-7.5 and a temperature of around 75-80°F. It is also important to maintain good water quality by performing regular water changes and keeping the aquarium clean.

Feeding Geophagus species is relatively easy, as they will accept a variety of different foods. They are omnivorous, meaning that they will eat both plant and animal-based foods. In the wild, they feed on a variety of small invertebrates, crustaceans, and other small animals. In the aquarium, they can be fed a diet of high-quality flakes or pellets, as well as live or frozen foods such as brine shrimp, bloodworms, and small pieces of shrimp or fish.

Conclusion

Geophagus species are attractive, peaceful cichlids that are popular among aquarists. They are relatively easy to care for and can make great additions to a community aquarium, as long as they are kept with other non-aggressive species of similar size. With the proper care and attention, Geophagus species can live for several years in the aquarium and provide their owners with many years of enjoyment.

Acestrorhynchus species

Acestrorhynchus is a genus of predatory freshwater fish belonging to the family Characidae, commonly known as the “banded pike-characins”. These fish are native to South America and are highly valued in the aquarium trade due to their striking appearance and predatory behavior.

There are over 30 recognized species within the Acestrorhynchus genus, with variations in size, coloration, and habitat preferences. The largest species can reach over 2 feet in length, while the smallest are less than 6 inches. The genus is primarily found in the Amazon Basin, but some species can also be found in other South American river systems.

Acestrorhynchus species are typically predatory and feed on smaller fish, insects, and crustaceans. They are known for their sharp teeth and quick strikes, making them a popular choice for aquarists looking for active and engaging fish to add to their tanks. However, due to their predatory nature, they are not suitable for all community aquariums and should be housed with caution.

In the wild, Acestrorhynchus species are found in a variety of habitats, including rivers, streams, and flooded forests. They are generally found in clear water with moderate to strong currents, and prefer areas with plenty of cover, such as submerged vegetation or fallen branches. They are also able to tolerate low oxygen levels, allowing them to survive in some of the more stagnant areas of their natural habitat.

In the aquarium, Acestrorhynchus species require a large tank with plenty of swimming room. They are best housed with other large, active fish that can hold their own against potential aggression. They prefer a well-oxygenated environment with moderate to strong water flow, and benefit from the addition of live or frozen foods to their diet.

Breeding Acestrorhynchus species in captivity can be challenging due to their predatory nature and specific environmental requirements. However, with proper care and attention, it is possible to successfully breed these fish. They are typically egg scatterers and will require a separate breeding tank with plenty of cover for the eggs and fry.

This species is not aggressive towards its own kind, and juveniles in particular exhibit a marked schooling instinct. While older individuals tend to be more solitary, they still group together from time-to-time. Therefore, it’s best to maintain them in groups of four or more for their well-being.

Reproduction

Unrecorded.

Notes

This species goes by several common names, including Bicuda or Uena in Brazil, Picudo in Ecuador, Picudo or Garza-challua in Peru, and Aguejeta in Venezuela.

The placement of the dorsal fin on this fish is mostly towards the back of the body, behind a vertical line drawn from the origin of the anal fin. This feature helps distinguish it from all other species in the same genus, except for B. lateristriga.

B. maculata can be distinguished from B. lateristriga by the presence of a thin, horizontal dark stripe only on the postorbital surface of the head in some specimens (rather than a prominent thin, dark stripe always extending from the rear of the orbit to the caudal peduncle), the lack of distinct, dark crossbars on the lobes of the caudal fin, the presence of randomly-distributed dark spots on the upper body, and a longer dorsal fin compared to B. lateristriga. Additionally, B. maculata has 73-84 predorsal scales and 17-23 scale rows between the dorsal fin origin and ventral midline, whereas B. lateristriga has 55-65 predorsal scales and 14-17 scale rows in the same area.

Both species have a broader dark midlateral stripe on their bodies, but it is more distinct in B. lateristriga. The color pattern of B. maculata can vary considerably, with some individuals being noticeably paler than others, and the broad midlateral stripe usually being less intense in these individuals.

There appears to be no discernible pattern in the distribution of Boulengerella across its range, but certain characteristics may be correlated with water type rather than geographic location.

Boulengerella can be distinguished from Ctenolucia, the only other genus in the family Ctenolucidae, by a number of features including having 87-124 (vs. 45-50) lateral line scales, a strongly (vs. weakly) developed fleshy appendage at the tip of the snout, and an absence (vs. presence) of fleshy flaps on the lower jaw.

Within the order Characiformes, the Ctenoluciidae family is further characterized by certain synapomorphic features, such as a tapered body shape, elongated jaw shape, and possession of many small teeth with curved tips arranged in a single series in each jaw.

The Characiformes order is known for its great diversity, with close to 2000 valid species distributed across 19 families. This taxonomic and morphological diversity has historically made it difficult for researchers to accurately determine genetic relationships between species, with many genera remaining unresolved. In some cases, individual study is the only way to address these issues.

Recent advances in molecular phylogenetics have enabled researchers to better understand the evolutionary relationships among different fish families. In 2005, Calcagnotto et al. published a study which suggested that the family Ctenoluciidae belongs to a trans-Atlantic, monophyletic clade alongside the families Lebiasinidae and Hepsetidae.

This clade further forms a sister group to Alestidae. However, other researchers such as Oliveira et al. in 2011 have concluded that the family Erythrinidae is also closely related to this grouping, with Hepsetidae and Alestidae being more distantly related. The use of molecular techniques has provided valuable insights into the evolutionary relationships of fish families, aiding in our understanding of the diversity of life in aquatic ecosystems.

References

Cuvier, G. and A. Valenciennes , 1850 – Histoire Naturelle des Poissons v. 22: i-xx + 1 p. + 1-532 + 1-91
Suite du livre vingt-deuxième. Suite de la famille des Salmonoïdes.
Calcagnotto, D., S. A. Schaefer and R. De Salle, 2005 – Molecular Phylogenetics and Evolution 36(1): 135-153
Relationships among characiform fishes inferred from analysis of nuclear and mitochondrial gene sequences.
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.
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.
Vari, R. P., 1995 – Smithsonian Contributions to Zoology 564: 1-97
The Neotropical fish family Ctenoluciidae (Teleostei: Ostariophysi: Characiformes): supra and intrafamilial phylogenetic relationships, with a revisionary study.