Xiphostoma cuvieri Spix & Agassiz, 1829; Xiphostoma ocellatum Jardine, 1841; Xiphostoma oseryi Castelnau, 1855; Xiphostoma longipinne Steindachner, 1876
Boulengerella: named for Belgian-British zoologist George Albert Boulenger (1858-1937).
cuvieri: named for French naturalist and zoologist Jean Léopold Nicolas Frédéric Cuvier (1769-1832).
- Order: Characiformes
- Family: Ctenoluciidae
The type locality of this species is listed as “Rivers of Brazil”, but current records suggest that it can be found in various parts of the Amazon basin, ranging from the Río Nanay in Peru to Amapá state in northeastern Brazil, as well as in the Río Orinoco in Venezuela and Colombia, and coastal drainages in Guyana, Suriname, and French Guiana.
The appearance of this species varies throughout its range. Individuals from the Río Orinoco, Guyana, and French Guiana tend to have a darker coloration compared to those from Peru, while specimens from the rios Tocantins and Juruena tend to have more lateral line scales (108-118) than those from the Oyapock (94-101), for example.
This particular species is considered to be pelagic, and it’s commonly found in flowing stretches of main river channels, larger tributaries of white and black water rivers, as well as floodplain lakes. As adults, they tend to associate themselves with these habitats.
Sexual maturity is reached when individuals of this species reach around 250 mm SL in size. The reproductive season typically occurs between November and March when water levels are at their highest.
In various instances, B. cuvieri has been observed to be collected alongside numerous other fish species, including the majority of its congeners.
Maximum Standard Length
The biggest recorded specimen of this species was 675 mm in size based on official records, but it seems that it can actually grow even larger, potentially exceeding 800 mm.
This particular species is only suitable for installation in public settings or the largest private aquariums.
This species is relatively easy to care for, but it does appreciate some surface cover in the form of floating or overhanging vegetation. It thrives in aquariums with a high proportion of dissolved oxygen and a moderate degree of water movement, so it’s recommended to use external filters, powerheads, and airstones as necessary.
In order to maintain stable water conditions and promote the well-being of the fish, it’s important to never add it to biologically-immature aquariums. Additionally, weekly water changes of 30-50% aquarium volume should be considered mandatory.
It’s also essential to have a tightly-fitting cover for the aquarium, as Boulengerella spp. are known for their jumping ability. To reduce the chances of the fish swimming into the glass, it may be beneficial to cover the back and sides of the aquarium, especially since this species can be skittish, especially in confined spaces.
- Temperature: 22 – 28 °C
- pH: 5.0 – 7.5
- Hardness: 18 – 215 ppm
An obligate predator feeding mostly on smaller fishes and insects in nature but in most cases adapting well to dead alternatives in captivity.
Bloodworms, small earthworms, chopped prawn, and similar options are suitable for smaller specimens, while adults can be offered strips of fish flesh, whole prawns or shrimp, mussels, live river shrimp, and larger earthworms.
It’s important to note that like most predatory fish, this species should not be fed mammalian or avian meat, such as beef heart or chicken. The lipids contained in these foods cannot be properly metabolized by the fish, which can cause excess fat deposits and even organ degeneration.
Additionally, feeding this species with “feeder” fish, such as livebearers or small goldfish, is not recommended. These fish carry the risk of introducing parasites or diseases and are not highly nutritious 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.
Aggressively territorial or very competitive species should be avoided, and the best choices for tankmates are similarly-sized fishes such as Cichla spp. and larger doradid or loricariid catfishes.
It’s also recommended to avoid other surface-dwelling fish, although some hobbyists have reported success keeping it alongside related Acestrorhynchus spp.
This species is not aggressive towards its own kind, and juveniles, in particular, exhibit a marked schooling instinct. Older individuals tend to be more solitary but still group together from time to time, and it’s best to maintain them in groups of four or more.
Given its eventual size and natural behavior, this species is largely unsuitable for home aquariums, and only a handful of private aquarists with appropriate facilities can house it long-term. It goes by various vernacular names, including Pirá-pacu, Pira-pucu, or Diente de cao (central Amazon), Bicuda or Uena (rio Tocantins), Bicuda (rio Tapajós), Aguejeta or Picua (Venezuela), and Moruwi or Pirapoko (Guyana).
One way to distinguish this species from all other ctenolucids except B. lucius and B. xyrekes is that the entire dorsal fin base is located anteriorly to a vertical through the anal fin origin. B. cuvieri differs from B. lucius in the presence (vs. absence) of a dark spot at the base of the median caudal fin rays, presence (vs. absence) of a dusky, somewhat diffuse lateral stripe, and absence (vs. presence) of randomly-distributed dark spots on the ventrolateral surface of the body.
B. cuvieri is very similar to B. xyrekes but can be distinguished by the absence (vs. presence) of an oblique stripe on the posteroventral portion of the third infraorbital, possession of 48-49 (vs. 44-46) vertebrae, and 94-124 (vs. 87-94) lateral line scales.
Boulengerella is different from Ctenolucia, the only other genus currently contained in the family Ctenolucidae, by a set of derived features, including possession of 87-124 (vs. 45-50) lateral line scales, the presence of a strongly (vs. weakly) developed fleshy appendage at the tip of the snout, and the absence (vs. presence) of fleshy flaps on the lower jaw.
Within the order Characiformes, the family Ctenoluciidae is also distinguished by a set of synapomorphic characters, including a tapering body shape, elongate jaw shape, and possession of many small teeth with curved tips arranged in a single series within each jaw.
Characiformes is one of the most diverse orders of freshwater fish, currently including close to 2,000 valid species distributed among 19 families. This tremendous taxonomic and morphological diversity has historically impaired the ability of researchers to resolve their genetic relationships, with many genera remaining incertae sedis.
Modern molecular phylogenetic techniques have allowed some progress, and research published by Calcagnotto et al. (2005) revealed some interesting hypotheses. Their results suggest Ctenoluciidae to belong to a trans-atlantic, monophyletic clade alongside the families Lebiasinidae and Hepsetidae, with this assemblage forming a sister group to Alestidae. Others, such as Oliveira et al. (2011), have concluded that the family Erythrinidae is also closely related to this grouping, with Hepsetidae and Alestidae being more distant.
- 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.