Marginatus Tetra (Hemigrammus marginatus) Care Guide
Hemigrammus marginatus is a slim, silvery South American tetra with yellow markings on the caudal fin, kept as a peaceful shoaling species.
Compiled by Aquairi from published sources · Published · Updated
Overview
Hemigrammus marginatus is a slim, silvery characid from South America, sometimes traded as the Bassam tetra. It is named for the yellow and black margins on the caudal fin. It is a peaceful, active shoaling species.
Taxonomy
- Family: Characidae
- Genus: Hemigrammus
- Scientific name: Hemigrammus marginatus
Habitat
Widely distributed across South America, including the Amazon and Orinoco basins, the Guaporé, and the São Francisco, Itapicuru, Paraná and Paraguay river basins in Brazil. It is a freshwater, benthopelagic species.
Tank requirements
- Minimum tank volume: 80 L
- Temperature: 22-28 °C (72-82 °F)
- pH: 6.0-7.5
- GH: 2-12 °dGH
- School size: at least 6 individuals
- Lifespan: 3-5 years
Diet
An omnivore with a comparatively low trophic level. In the aquarium it accepts dried flakes and granules alongside small live and frozen foods.
Compatibility
A peaceful mid-water shoaling fish suitable for community tanks. It associates well with Corydoras and pencilfish and should be kept away from fin-nippers.
Conservation status
IUCN Red List: Least Concern (assessed 2021).
Marginatus Tetra (Hemigrammus marginatus) Breeding Guide
Overview
Hemigrammus marginatus is a widely distributed characin recorded from the Sao Francisco, Itapicuru, Parana and Paraguay basins of Brazil, the Guapore and Amazon basins, and the Orinoco basin. It reaches around 4.5 cm SL (reported up to about 8 cm TL) and lives at roughly 20-28 C. Verified species-specific breeding accounts are scarce; the approach below follows the well-documented Hemigrammus egg-scattering pattern shared by congeners such as H. rodwayi and H. unilineatus.
Sexing
In Hemigrammus generally, females are fuller and more rounded in the body than males, especially when carrying eggs. Detailed sexual dimorphism specific to H. marginatus is not documented in the consulted sources.
Conditioning
Condition the group on plenty of small live and frozen foods until females are visibly rounded. Spawning can be attempted in a group of around six of each sex or in selected pairs, following the typical genus method.
Breeding Setup
- Spawning tank around 18 x 10 x 10 inches, kept very dimly lit.
- Soft, acidic water typical for the genus (around pH 5.5-6.5, low hardness); the species tolerates roughly 20-28 C.
- Clumps of fine-leaved plants such as java moss or spawning mops, or a mesh base to protect the eggs.
- Gentle aeration from a sponge filter.
Spawning Behavior & Trigger
As an egg-scattering characin, the species is expected to scatter non-adhesive eggs among plants with no parental care. Soft acidic water and subdued lighting are the usual triggers for Hemigrammus. Adults should be removed once eggs are seen to prevent predation.
Common Challenges
Egg predation by the adults is the main risk, as in all egg-scattering tetras. Because species-specific spawning data for H. marginatus are limited, breeders should monitor results and adjust water chemistry within the genus-typical soft, acidic range.