Taxonomy & naming
Saccoderma hastata was originally described as Odontostilbe hastata by Carl H. Eigenmann in 1913, based on material from the Magdalena River basin of Colombia. Leonard P. Schultz transferred the species to the genus Saccoderma in 1944, where it remains today. Eschmeyer's Catalog of Fishes (Fricke, Eschmeyer & Fong) is the authority for the valid name Saccoderma hastata (Eigenmann, 1913); the parenthetical authority reflects the original description in a genus other than the one now accepted.
The species belongs to the subfamily Cheirodontinae within Characidae — a group of diminutive, mostly South American characins. The genus Saccoderma is distinguished within the subfamily by a small skin pouch associated with jaw or head structures, from which the name derives (Latin sacculus, a small bag, combined with Greek derma, skin). The 2017 checklist of freshwater fishes of Colombia confirms the species' presence in that country's ichthyofauna and records the Eigenmann 1913 description.
Morphology
Saccoderma hastata is a small, slender characid reaching approximately 1.5 in standard length — a size typical for the subfamily Cheirodontinae. Like most cheirodontines it has a laterally compressed, fusiform body with the large eyes and small mouth characteristic of microphagous characins.
A notable feature recorded in the species' name is the presence of retrorse hooks on the rays of the caudal and anal fins, which is reflected in the specific epithet hastata — Latin for 'armed with a spear.' Such fin hooks are known from several characid groups and are thought to function in male–male or spawning interactions. Beyond this, detailed meristic data for the species are sparse in the accessible literature.
Habitat
Saccoderma hastata is endemic to the Magdalena River basin in Colombia, one of South America's major trans-Andean river systems. The Magdalena drains a large portion of Colombia's interior between the Eastern and Central Andes cordilleras before emptying into the Caribbean Sea.
FishBase characterises the species as benthopelagic in freshwater habitats, with preferred water conditions of 73–81 °F, pH 6.0–7.0, and hardness of 2–8 dH — moderately soft, slightly acidic to neutral water consistent with lowland Magdalena tributaries. As a small cheirodontine it likely inhabits margins, flooded areas, and well-vegetated shallows within its river-basin range.
Feeding
FishBase classifies Saccoderma hastata as an omnivore, consistent with the Cheirodontinae generally. Members of the subfamily typically feed on fine particulate matter including microinvertebrates, zooplankton, and algae, gleaned from the water column and substrate surfaces.
In the aquarium, cheirodontine characins of similar size readily accept small prepared foods — micro-pellets and finely crushed flake — alongside live and frozen offerings such as newly hatched brine shrimp, Daphnia, and microworms. Specific published feeding observations for this species are not available in the accessible literature.
Mating
No specific field or laboratory observations of mating behaviour in Saccoderma hastata have been published in the accessible literature. Based on its placement in Cheirodontinae, the species is expected to be an egg-scattering open spawner, with males likely competing for access to receptive females through displays that may involve the fin hooks for which the species was named.
The retrorse hooks on caudal- and anal-fin rays, which inspired the epithet hastata (spear-armed), may play a role in male–male interactions or in maintaining contact with the female during spawning — a function proposed for similar structures in other characids. No parental care is expected.
Breeding
No detailed captive or field breeding records for Saccoderma hastata are available in the accessible literature. By analogy with other small cheirodontines, spawning is expected to follow the characid norm: adhesive or semi-adhesive eggs scattered among fine-leaved aquatic vegetation or substrate, with no parental care and adults likely to consume eggs if given the opportunity.
Incubation period, clutch size, and fry development specifics remain undocumented for this species. Aquarists attempting to breed small Colombian cheirodontines typically provide dense planting or spawning mops, slightly acidic to neutral soft water near the lower end of the thermal range, and remove adults promptly after spawning. Data sparse.
In the aquarium
Saccoderma hastata is rarely encountered in the ornamental fish trade and is largely unknown outside specialist collections. As a small, peaceful cheirodontine, it would in principle be suited to a well-planted community aquarium with soft, slightly acidic water (pH 6.0–7.0, 73–81 °F, 2–8 dH) and similarly sized tankmates that will not outcompete it at feeding.
Given its small size (around 1.5 in SL) and presumed schooling nature, a group of at least six to eight individuals would be appropriate, in an aquarium of modest size but with subdued lighting, dark substrate, and dense marginal planting to mirror the Colombian lowland habitats from which it originates. Specific husbandry guidance is not available in the published or hobbyist literature; keepers should rely on generalised best practices for small Colombian characins.
Conservation
Saccoderma hastata is assessed as Least Concern (LC) on the IUCN Red List, with the most recent assessment recorded in 2014. The Magdalena River basin, while subject to considerable anthropogenic pressure from agriculture, deforestation, and urban expansion in Colombia, is a large and hydrologically complex system that supports a highly diverse ichthyofauna.
No specific conservation actions or population monitoring programmes are documented for this species. Its LC status reflects the absence of evidence for significant population decline rather than comprehensive survey data. As a small, obscure characid with no commercial value in the ornamental trade and no food fishery importance, it falls outside the scope of most targeted conservation or research effort, and the quality of available data for the species remains limited.