Taxonomy & naming
Prochilodus magdalenae was described by the Austrian ichthyologist Franz Steindachner in 1879, with a type locality in the Magdalena River basin of Colombia, from which the species epithet derives. It belongs to the family Prochilodontidae — the flannelmouth characiforms, a small family of detritivorous river fish distinguished by their protrusible, sucker-like mouths adapted for scraping periphyton and organic matter from submerged surfaces — within the order Characiformes.
The genus Prochilodus sits apart from the piranhas, pacus and silver dollars of Serrasalmidae covered elsewhere in this family group; it is grouped here among the "minor characins" alongside the hemiodontids and curimatids as a shoaling, largely non-predatory river grazer rather than a serrasalmid. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) is the reference for the currently accepted combination Prochilodus magdalenae, and the vernacular name "bocachico" (Spanish for "small mouth") is used throughout Colombia for this and related Prochilodus species.
Morphology
Prochilodus magdalenae has the characteristic prochilodontid build: a moderately deep, laterally compressed, silvery body, a small protrusible mouth with fleshy, sucker-like lips adapted for scraping substrate, and a forked tail. FishBase records a maximum size of 20 in standard length, with most reports citing roughly 19.5 in SL and a maximum recorded weight of about 905 g; fish reach sexual maturity at around 9.5 in SL, well short of maximum size.
As with other Prochilodus, the mouth is the functional giveaway of its ecology: rather than grasping or biting prey, the protrusible lips form a disc-like scraping tool that the fish uses to graze periphyton and detritus off rocks, wood and sediment. This is a substantially larger, more heavily built fish than the small tetra-type characins most aquarists picture, and its silhouette and feeding apparatus reflect a life spent grazing river-bottom substrate rather than hunting.
Habitat
The species is native to Colombia, recorded from the Atrato, Sinú and Cauca-Magdalena river basins — a range centred on the Magdalena River system, the country's principal river and one of the most heavily used and altered watersheds in northern South America. It is a benthopelagic freshwater fish of tropical lowland rivers, typically found in main river channels and floodplain habitats rather than headwater streams.
Like other migratory Prochilodontidae, P. magdalenae depends on the connectivity of its river system: it moves between main-channel and floodplain habitats with the seasonal flood pulse, and this migratory life history is central to both its ecology and its vulnerability, since dams and other barriers that fragment river connectivity disrupt the very movements the species relies on to feed, grow and spawn.
Feeding
Prochilodus magdalenae is a detritivore-illiophagous grazer, not a predator. It feeds on periphyton — the algae, bacteria, fungi, small invertebrates and organic and inorganic detritus that accumulate on submerged substrate — scraping this film from rocks, wood and sediment with its specialised, protrusible mouth. This diet places it at a very different trophic level from the piranhas and larger predatory characins covered elsewhere in this family group.
The same detritivorous habit that makes it ecologically important in the wild — recycling nutrients and organic matter through river food webs — also makes it economically attractive in aquaculture: farmed bocachico can be raised on comparatively low-cost feed regimes because a meaningful share of its diet needs come from natural pond productivity rather than purchased feed, an advantage cited as reducing production costs significantly relative to carnivorous farmed fish.
Mating
Prochilodus magdalenae is best understood as a migratory food fish, not a fish with a documented hobby-breeding courtship sequence. Spawning is tied to the "subienda" — a mass upstream migration timed to seasonal rises in water level — during which large aggregations of adults move from the main river channel toward spawning grounds. This migratory, flood-pulse-triggered reproductive strategy is shared broadly across Prochilodus and Semaprochilodus and is fundamentally different from the paired, territorial courtship described for substrate-spawning piranhas in this same family group.
Because reproduction depends on long-distance migration and environmental cues tied to river hydrology, there is no meaningful account of pairing behaviour, courtship displays or external sexual dimorphism for this species in aquarium or even close aquaculture-holding conditions — data on that scale of behavioural detail is sparse and not something this species' biology or its commercial handling has generated.
Breeding
This is a migratory food-fish, not a home-aquarium breeding candidate. In the wild, Prochilodus magdalenae spawns during the subienda migration, releasing eggs into river channels and overflow waters where flood-pulse hydrology and current carry and disperse them; there is no parental care of eggs or fry. Commercially, the species is propagated at scale in Colombian aquaculture using hormone-induced spawning protocols, a standard technique for migratory characiforms whose reproduction depends on environmental triggers that captive tanks and ponds cannot reliably reproduce on their own.
Given its adult size (up to roughly 20 in SL), its dependence on long-distance migration to spawn, and its status as a hormone-bred aquaculture and food-fish species, Prochilodus magdalenae is essentially never bred — or kept — in the home aquarium. Any reproduction of this species outside its native rivers happens in farm and hatchery settings, not display tanks.
In the aquarium
Prochilodus magdalenae is not a realistic aquarium fish. An adult approaching 19.5 in SL and up to roughly 900 g requires enormous, purpose-built holding facilities — the scale of aquaculture ponds and large public-aquarium systems, not home tanks — and its migratory, flood-pulse-triggered biology cannot be replicated in captivity in any way that supports normal behaviour or breeding.
Where the species is genuinely significant is as food and as an aquaculture subject: bocachico is a major component of Colombian freshwater fisheries and a farmed species valued for its fast growth and its ability to derive much of its nutrition from natural pond productivity rather than purchased feed. Prospective keepers of characins from this family group should look to the smaller hemiodontids, curimatids and other minor characins actually suited to display aquaria; P. magdalenae belongs in that broader survey as a contrast case — a large, wild-caught-and-farmed river grazer, not a tank fish.
Conservation
The IUCN Red List currently lists Prochilodus magdalenae as Data Deficient, meaning the available population data are judged insufficient to assign the species a specific threat category. Separately, well-documented catch data from the bocachico fishery show a dramatic decline: reported landings fell from roughly 40,000 tonnes in 1975 to approximately 9,500 tonnes per year in the 2013–2016 period, a decline of more than three-quarters over four decades. Cited pressures on the fishery and its habitat include sustained overfishing during the migratory spawning period, harvesting of undersized fish, and habitat degradation across the Magdalena-Cauca system — deforestation, drying and disturbance of floodplain wetlands, agrochemical and mining contamination, sedimentation, and the construction of dams and hydropower infrastructure that fragment the river connectivity the species' migratory life cycle depends on.
Because P. magdalenae is both an important subsistence and commercial food fish and a species whose reproduction is now substantially supported by hatchery and aquaculture propagation, its conservation story is closely tied to fisheries management — enforcement of size limits and migratory-season protections, and maintaining river connectivity — rather than to aquarium trade pressure, which is not a factor for this species.