Taxonomy & naming
Hoplias patana was described by the French naturalist Achille Valenciennes in 1847, placing it in the genus Hoplias within the family Erythrinidae — the trahiras or wolf fishes, a small Neotropical family of air-breathing, elongate predatory characiforms that also includes Erythrinus and Hoplerythrinus. The genus name Hoplias derives from the Greek hoplon, "weapon" or "armament," a fitting reference to the heavy, conical dentition shared across the genus.
Hoplias has historically been treated as a taxonomically difficult genus: for decades most Central and South American trahiras were lumped under the wide-ranging "Hoplias malabaricus," which molecular and morphological work has since shown to be a complex of multiple distinct species. Hoplias patana is one of the recognized species within that broader trahira group; distinguishing it reliably from close congeners such as H. malabaricus and H. aimara in the field relies on subtle morphometric and meristic characters rather than obvious external field marks, and much of the popular literature on "Hoplias" care does not distinguish between species.
Morphology
Like other trahiras, Hoplias patana has the classic Erythrinidae body plan: a thick, cylindrical, only mildly compressed body, a broad flattened head, and a large terminal mouth armed with a formidable set of heavy, conical teeth designed for gripping rather than shearing prey. FishBase records a maximum size of 15.5 in standard length for the species — modest compared with the largest congener, Hoplias aimara, which exceeds a metre in length and is markedly more powerful and aggressive.
The dorsal and anal fins sit well back on the body, close to the tail, an arrangement typical of ambush predators that rely on a fast strike rather than sustained pursuit. As with other Erythrinidae, Hoplias species possess an accessory air-breathing organ, allowing them to tolerate low-oxygen water and survive in stagnant or seasonally depleted pools — a trait documented in the related H. malabaricus and consistent across the genus.
Habitat
FishBase records Hoplias patana from French Guiana, around Cayenne, placing it within the freshwater drainages of the Guiana Shield. Data specific to this species' habitat preferences within that range is sparse in the sources consulted.
More broadly, Erythrinidae as a family — documented in detail for the related Hoplias malabaricus — are noted for their tolerance of a very wide range of freshwater conditions, from fast-flowing streams to near-stagnant, low-oxygen pools, aided by their accessory air-breathing capacity. Hobby sources covering Hoplias care in general cite a workable aquarium temperature around 79 °F and a pH range of roughly 6.0–7.5, though these figures are drawn from general Hoplias husbandry accounts rather than data specific to H. patana, and should be treated as a starting point rather than a documented species requirement.
Feeding
Hoplias patana is a piscivorous ambush predator, consistent with every documented member of its genus. Hobby and field sources describe Hoplias as sitting motionless, often concealed among cover, before striking prey that comes within range; the diet is overwhelmingly fish, supplemented opportunistically by small terrestrial invertebrates and other animals that fall into the water.
In the aquarium, this translates to a strict need for meaty, whole or cut fish and similar foods — prawn, and other fish — rather than a flake- or pellet-based diet; Hoplias and other trahiras are reported to resist dry foods. Any tankmate must be too large to be swallowed, since a Hoplias will treat any fish it can fit in its mouth as a meal, not merely a rival.
Mating
No courtship behaviour specific to Hoplias patana was found in the sources consulted. In the wider genus, breeding accounts (documented for related Hoplias species kept in the hobby) describe a male preparing a nest site — typically a shallow pit dug into the substrate — ahead of spawning, with an increase in water temperature reported as a trigger for reproductive activity in captive fish.
No reliable external sexual dimorphism for Hoplias patana specifically was found in the cache; data is sparse for this species and this account should not be taken to imply a documented sexing method.
Breeding
Breeding data specific to Hoplias patana was not found in the sources consulted. In the wider genus, several Hoplias species are documented as substrate nest-spawners: hobby accounts of related Hoplias (e.g., H. malabaricus) describe a male digging a shallow pit into which a large clutch — reportedly numbering in the thousands of yellowish eggs — is laid, with the male guarding the nest and the resulting larvae. Reported spawning triggers include raising the water temperature into the upper 20s °C.
Whether Hoplias patana itself has been bred in captivity is not established in the sources available here; trahiras in general are only rarely bred in the aquarium hobby, and this account should be read as describing genus-level behaviour rather than a confirmed record for this species.
In the aquarium
Hoplias patana should be kept as a solitary specimen in a large, securely covered aquarium sized well beyond its 15.5 in maximum published length, since related Hoplias are documented as capable of jumping and as aggressive toward any tankmate they can engulf. Practical Fishkeeping's coverage of Hoplias as predators describes the genus bluntly as "wolves of the water": solitary ambush hunters with strong conical teeth capable of inflicting a serious bite, unsuitable for community tanks under any circumstances.
Provide dense cover — driftwood, roots or heavy structure — for the fish to ambush from, robust filtration to handle a large, messy piscivore's bioload, and a diet of whole or cut fish and other meaty foods; expect the fish to refuse dry food. Given the limited species-specific data available, keepers should also budget for the possibility that adult size or temperament could exceed what has been documented here, and should never keep this fish with anything it can swallow or that could be hurt by its bite.
Conservation
Hoplias patana has not been evaluated by the IUCN Red List (Not Evaluated), which is unsurprising for a taxonomically obscure member of a genus that has only recently begun to be resolved into distinct species from the former "Hoplias malabaricus" complex. No population trend, threat assessment or trade-pressure data specific to this species was found in the sources consulted.
As a Guiana Shield freshwater fish, H. patana would be expected to face the general pressures common to the region's freshwater habitats — but no source-backed, species-specific conservation information is available here, and this account deliberately says no more than that.