Boulengerella lateristriga (BOULENGER, 1895) – Striped Pike ‘Characin’

Boulengerella is a genus of freshwater fishes belonging to the family Ctenolucidae and the order Characiformes. The genus includes six recognized species, with the most commonly known species being Boulengerella maculata, also known as the spotted pike characin or bicuda. These fishes are found in the blackwater rivers and tributaries of South America, mainly in the Amazon River basin.

One of the defining features of Boulengerella is their elongated, streamlined body shape, which is similar to that of the northern pike. They have a large mouth with sharp teeth, which they use to capture prey. Their coloration can vary between species, but generally, they have a silver or grey base color with dark stripes or bars running vertically down their body.

Boulengerella is known 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).

Boulengerella is an obligate predator that feeds mostly on smaller fishes and insects in the wild, but in most cases, adapts well to dead alternatives in captivity. Smaller specimens can be offered bloodworm, small earthworms, chopped prawn, and similar foods, while adults will accept strips of fish flesh, whole prawns or shrimp, mussels, live river shrimp, and larger earthworms.

These fishes are relatively unfussy, although they appreciate some surface cover in the form of floating or overhanging vegetation. To ensure optimal conditions, it is recommended to maintain a high level of dissolved oxygen and moderate water movement in the aquarium by using external filters, powerheads, airstones, etc., as necessary.

Boulengerella is named after Belgian-British zoologist George Albert Boulenger, who was a prominent ichthyologist in the late 19th and early 20th centuries. The largest officially recorded specimen of Boulengerella measured 258 mm.

In terms of their behavior, Boulengerella are 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, with the best choices being similarly-sized, placid fishes such as Geophagus or Acestrorhynchus spp. and many doradid or loricariid catfishes.

Boulengerella is relatively easy to care for in captivity and can make a fascinating addition to a well-maintained aquarium. However, it is essential to choose tankmates carefully, provide adequate surface cover, and maintain optimal water conditions to ensure their well-being. This fish should never be added to biologically-immature aquaria, and weekly water changes of 30-50% aquarium volume should be considered mandatory.

A tightly-fitting cover is also essential as Boulengerella spp. are prodigious jumpers, and it may also prove beneficial to cover the back and sides of the aquarium to reduce the chances of it swimming into the glass since it can be skittish, especially in confined surroundings.

Ctenolucidae is a family of freshwater fishes belonging to the order Characiformes. This family includes two genera, Boulengerella and Ctenolucius, with a total of 12 recognized species. These fishes are commonly known as pike characins or pike ctenoluciids due to their similar appearance to the northern pike (Esox lucius).

The distribution of Ctenolucidae ranges from Panama to South America, with some species found in the Amazon River basin, while others are found in the Orinoco River basin. They inhabit blackwater rivers and tributaries, where the water is stained darkly with humic acids and other compounds released by decomposing organic matter.

One of the defining features of Ctenolucidae is their elongated, streamlined body shape, which is similar to that of the northern pike. They have a large mouth with sharp teeth, which they use to capture prey. Their coloration can vary between species, but generally, they have a silver or grey base color with dark stripes or bars running vertically down their body.

Ctenolucidae are obligate predators that feed mainly on smaller fishes and insects in the wild but can adapt well to dead alternatives in captivity. They are best fed with strips of fish flesh, whole prawns or shrimp, mussels, live river shrimp, and larger earthworms.

These fishes are relatively unfussy, although they appreciate some surface cover in the form of floating or overhanging vegetation. To ensure optimal conditions, it is recommended to maintain a high level of dissolved oxygen and moderate water movement in the aquarium by using external filters, powerheads, airstones, etc., as necessary.

Ctenolucidae is known 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).

The dorsal-fin base of Ctenolucidae is located mostly posterior to a vertical line through the anal-fin origin, which sets them apart from all other congeners except B. maculata. B. lateristriga can be distinguished from B. maculata by the presence of a thin, dark stripe extending from the rear of the orbit to the caudal peduncle (vs. a stripe limited to the postorbital surface of the head when present), the presence (vs. absence) of distinct, dark crossbars on the lobes of the caudal-fin, the absence (vs. presence) of randomly-distributed dark spots on the upper body, 55-65 (vs. 73-84) predorsal scales, 14-17 (vs. 17-23) scale rows between the dorsal-fin origin and ventral midline, and a relatively short (vs. relatively long) dorsal-fin. Both species also have a broader dark midlateral stripe on the body, which tends to be more well-defined in B. lateristriga than in B. maculata.

Boulengerella can be distinguished from Ctenolucia, the only other genus currently contained in the family Ctenolucidae, by several 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.

The family Ctenoluciidae is also distinguished by a set of synapomorphic characters within the order Characiformes, 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.

The taxonomical and morphological diversity of Characiformes has historically made it difficult for researchers to resolve genetic relationships, with many genera remaining incertae sedis. However, modern molecular phylogenetic techniques have allowed some progress in understanding the relationships within this group.

A study by Calcagnotto et al. (2005) suggested that Ctenoluciidae belongs to a trans-Atlantic, monophyletic clade alongside the families Lebiasinidae and Hepsetidae. This assemblage further forms a sister group to Alestidae. Other studies, 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.

In terms of their behavior, Ctenolucidae are 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, with the best choices being similarly-sized, placid fishes such as Geophagus or Acestrorhynchus spp. and many doradid or loricariid catfishes. This species is not aggressive towards conspecifics, with juveniles in particular exhibiting a marked schooling instinct. Older individuals tend to be more solitary but still group together from time-to-time, and it’s best maintained in numbers of four or more.