Taxonomy & naming
Parastremma album was described by George Dahl in 1960 from specimens collected in the Sandó River, a tributary of the Baudó River on the Pacific versant of the Cordillera Occidental in Chocó, Colombia. The holotype is deposited at the Field Museum of Natural History (FMNH) in Chicago. Eschmeyer's Catalog of Fishes (CAS) recognises the species as valid under the authorship Dahl, 1960.
The genus Parastremma is placed in the subfamily Rhoadsiinae within Characidae, a subfamily of small characids associated with Pacific-draining river systems in northwestern South America and Central America. The genus contains only three known species: P. album, P. pulchrum Dahl 1960, and P. sadina Eigenmann 1912 — all three described from Colombia's Pacific-versant drainages. Comprehensive freshwater-fish checklists for Colombia recognise P. album as a valid endemic species in that drainage.
No vernacular common name has been recorded for this species in any major ichthyological database or hobbyist source.
Morphology
The holotype male of Parastremma album measures 3.5 in standard length (SL), placing it among the larger members of the subfamily at roughly 3.5 in SL maximum. Beyond the type-series data, published morphological descriptions for this species are sparse.
As a rhoadsiin characid, P. album presumably shares the family's general body plan: a laterally compressed, fusiform body with the characteristic adipose fin, a terminal mouth, and a full complement of Weberian ossicles. The specific epithet album (Latin: white) likely references a pale colouration or whitish body tones observed in fresh specimens, though a detailed colour description in life has not been widely published. No aquarium observations exist to supplement the dry type-series record.
Habitat
Parastremma album is known from the Sandó River, a tributary of the Baudó River, in the Pacific-draining portion of the Cordillera Occidental in Chocó department, Colombia. The Baudó basin drains a coastal mountain range with extremely high rainfall — among the highest annual precipitation figures recorded anywhere on Earth — producing fast, clear, soft, and naturally acidic rivers and streams running through dense lowland and foothill rainforest.
The species is characterised as benthopelagic in freshwater. Mountain-stream tributaries in the Baudó system flow over sand and gravel substrates with abundant leaf litter, submerged wood, and riparian vegetation providing structural cover. Water temperatures in Pacific-versant Colombian rivers at this elevation range across a broad band depending on altitude and season; the region supports an exceptionally high density of endemic freshwater fishes.
No detailed field measurements of water chemistry specifically from P. album collection sites have been published.
Feeding
No published dietary studies exist for Parastremma album. The species is presumed to be an omnivore with micropredatory tendencies, consistent with the feeding ecology documented for other small characids in similar Pacific-versant Neotropical streams — a diet likely incorporating small aquatic invertebrates, zooplankton, insect larvae, and organic detritus.
Small rhoadsiin and associated characids in high-rainfall Colombian drainages typically exploit the high invertebrate productivity of forest-floor streams. Given the near-absence of this species from the aquarium trade, no captive feeding observations are available to supplement the inference from family-level ecology.
Mating
No mating observations have been published for Parastremma album in the wild or in captivity. For a small characid in subfamily Rhoadsiinae, the most likely reproductive strategy is egg-scattering with no parental care — the predominant mode across Characidae, in which males and females release eggs and sperm simultaneously among fine-leaved vegetation, submerged roots, or over gravel substrate.
If P. album follows this pattern, courtship would involve the male pursuing and nudging the female to stimulate spawning, with the pair executing rapid spawning rushes among vegetation. There is no evidence of territoriality, nest construction, or other derived mating behaviour in the genus.
Breeding
No breeding records exist for Parastremma album in captivity, and no field data on reproductive seasonality, clutch size, or larval development have been published. By analogy with other small Characidae, the species is expected to produce small, adhesive or semi-adhesive eggs scattered among fine-leaved plants or over the substrate, which hatch without parental attendance.
Typical incubation periods for small tropical characids at warm temperatures range from 24 to 72 hours, with free-swimming fry appearing shortly after. The complete absence of this species from the hobby means that any such inference remains untested.
In the aquarium
Parastremma album is not established in the aquarium hobby and has not been kept or bred in captivity to any recorded extent. No husbandry guidelines, water-parameter recommendations, or compatibility notes exist for this species.
Given its origin in the Baudó basin's soft, naturally acidic, cool-to-warm mountain streams, a biotope-inspired approach — soft, slightly acidic water, moderate temperatures, subdued lighting, and heavy plant or wood cover — would be a logical starting point if the species were ever to enter the trade. Its rarity, restricted range, and Data Deficient conservation status make wild collection a sensitive matter. Any captive stock would represent significant scientific and conservation value.
Conservation
Parastremma album is assessed as Data Deficient (DD) on the IUCN Red List (2022.2 assessment). The DD listing reflects the near-complete absence of population data, distributional surveys, and threat assessments for this species — not necessarily that it is secure, but that the evidence to evaluate its status is lacking.
The species is endemic to a single river basin in one of the most threatened biodiversity hotspots in the world. Chocó's forests face severe pressure from illegal gold mining, agricultural expansion, logging, and infrastructure development, all of which degrade stream habitats and elevate sediment loads in rivers. A species known from only a small portion of a single drainage, with no population monitoring and minimal scientific attention, is inherently vulnerable to localised extinction events. Freshwater endemic checklists for Colombia list P. album as a species of conservation concern warranting further survey work.