Taxonomy & naming
Hemigrammus bellottii was originally described by Franz Steindachner in 1882, placing it in the large genus Hemigrammus within the family Characidae. The authority is parenthetical — (Steindachner, 1882) — indicating the species was placed in a different genus at first description before being moved to Hemigrammus, where Eschmeyer's Catalog of Fishes (CAS) records it as the current valid name.
The species belongs to a genus of roughly 70 small characids distributed widely across northern and central South America. Hemigrammus is distinguished from the closely related Hyphessobrycon by the presence of scales on the lower lobe of the caudal fin, a character that can be subtle in small preserved material. H. bellottii occupies a modest position in the literature — well-documented by its original description and by subsequent FishBase and IUCN treatments — but has attracted renewed interest through a 2026 study on its reproductive biology in mining- and agriculture-impacted Amazonian waters.
Morphology
A slender, moderately laterally compressed tetra reaching 1.5 in standard length (SL), with total length to approximately 1.5 in. The body profile is elongate for the genus, and the fish moves with the quick, slightly nervous flicker common to schooling characids of open-water microhabitats.
The colour pattern centres on a silver horizontal stripe running from the operculum to the caudal peduncle, overlaid by a narrow dark line that intensifies posteriorly toward the tail base. The most distinctive mark is the red semi-circle around the eye — a patch of concentrated pigment above and around the iris — that gives the fish its Golden Glowlight trade name and distinguishes it at a glance from many superficially similar Hemigrammus. The overall ground colour is silvery and translucent, and the fins are largely clear to lightly pigmented.
Habitat
Hemigrammus bellottii is recorded from the Solimões, Negro, and Maroni river basins, with its broader confirmed range spanning the Amazon and Orinoco lowlands of Brazil, Colombia, Ecuador, Peru, and Venezuela. The IUCN assessment specifies a preference for clear and black-water tributaries on terra firme — that is, higher, non-flooded ground outside the seasonally inundated varzea and igapó — rather than floodplain habitats.
Within those drainages the species favours calm, sluggish waters rich in macrophytes and submerged cover: tributary margins, flooded banks, and quieter backwaters. FishBase classifies it as benthopelagic and records it in both headwaters and lower river reaches. Water temperatures through most of its range run 73–81 °F, and its sympatric occurrence with species such as Hyphessobrycon bentosi and Paracheirodon spp. places it firmly in the characteristic community of Amazonian blackwater and clearwater small-tetra biotopes.
Feeding
Hemigrammus bellottii is an insectivore-dominated carnivore in the wild. FishBase diet records list arthropods as the primary food, with aquatic insect larvae — caddisfly larvae (Trichoptera), chironomid midges (Chironomidae), and mayfly nymphs (Ephemeroptera) — accounting for the bulk of gut-content samples. Terrestrial insects falling from overhanging vegetation, including ants, are also taken.
In the aquarium the species accepts a wide range of small prepared foods — quality micro-pellets, crushed flake — and responds well to regular offerings of small live or frozen invertebrates such as Daphnia, newly hatched brine shrimp, and frozen bloodworm or Cyclops. Its small mouth limits particle size; foods should be appropriately fine. A varied diet with live or frozen components keeps the fish in best condition and encourages the natural schooling and feeding behaviour that makes the species most visible and active.
Mating
Like most small Hemigrammus, H. bellottii is an egg-scattering open spawner. In the wild, reproductive activity in Colombian populations (Leticia area) peaks during the wet season from approximately April through August, when rising water levels, reduced conductivity, and abundant food trigger breeding condition in mature fish. The species forms loose schools and spawns without pair bonding or territory defence.
Males and females in breeding condition show mild dimorphism — females become noticeably plumper as the ovaries ripen — and spawning is preceded by active pursuit through vegetation. There is no parental investment; adults are indifferent to eggs once released and will consume them given the opportunity.
Breeding
Spawning in captivity follows the classic egg-scattering characid pattern: conditioned adults scatter adhesive eggs freely among fine-leaved plants or synthetic spawning mops. A dimly lit breeding tank furnished with Java moss or a dense spawning mop, soft and slightly acidic water (pH 6.0–6.5, low hardness), and temperatures in the mid-to-upper 20s Celsius replicates the soft blackwater tributaries the species favours and encourages spawning.
Eggs are small and sticky, attaching to plant fibres. Because the adults offer no care and will eat eggs immediately, breeders remove the spawning medium to a separate rearing vessel or net the adults out once spawning has been observed. Incubation at 79 °F takes roughly 24–36 hours for most small Hemigrammus; fry are free-swimming within a few days and need very fine first foods — infusoria or commercial liquid fry food — before graduating to newly hatched brine shrimp nauplii. Growth to sellable size is moderate and the species has been collected for the ornamental trade, though captive breeding at scale is straightforward.
In the aquarium
Hemigrammus bellottii is a peaceful, gregarious schooling tetra best kept in groups of eight or more. A school of a dozen or more fish schooling in open water is markedly more confident and active than a small group, and the red eye-mark and silver stripe are shown off far better when the fish are relaxed and in formation. A tank of 23.5 in or more gives adequate swimming room for a group.
Water chemistry should lean toward the soft, acidic, warm side consistent with its Amazonian blackwater origins: pH 6.0–6.5, low hardness, and 73–81 °F are appropriate targets, though the species tolerates some deviation from ideal. Filtration should turn over the water gently — strong currents are not natural to the calm tributaries it inhabits. A biotope-style setup with dark substrate, tannin-stained water, and fine-leaved plants suits it well and emphasises its colouration. Tankmates should be similarly small and peaceful; it cohabits naturally in the wild with other Hemigrammus, Hyphessobrycon, and Paracheirodon species, and these make logical companions in the aquarium. The species is not commonly seen in the trade but is occasionally available from specialist importers.
Conservation
Hemigrammus bellottii is assessed as Least Concern (LC) on the IUCN Red List, with the assessment published in 2023 based on an evaluation by F. Lima dated 04 March 2021. The IUCN notes that the species is abundant across most of its range, which spans the Amazon and Orinoco lowlands of five South American countries, and that its population trend is stable. No obvious threats are reported at the species level, and it occurs within protected areas.
It is occasionally captured for the ornamental fish trade but this is not considered a significant pressure given the breadth and abundance of the population. A 2026 study examined its reproductive biology in areas of the Amazon basin affected by mining and agricultural activity — a reminder that local habitat degradation can affect even widespread species, and that the current Least Concern assessment reflects range-wide abundance rather than the absence of any localised pressure.