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Marbled Headstander
Abramites hypselonotus
A massive, beautifully banded headstander with a highly arched back. Swims constantly at a downward angle. Unlike its peaceful cousins, it is a boisterous, nippy colossus (15 cm) that will mercilessly devour and destroy any live plants in the aquarium.
Class:Actinopteri
Order:Characiformes
Family:Anostomidae
Genus:Abramites
Species:Abramites hypselonotus
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Water Temperature
23 - 27 °C
pH Value
6 - 7.5
Water type
Freshwater
Adult size
14 cm
Minimum tank volume
>= 100 L
Minimum group
>= 1
GH
4 - 15 dGH
KH
2 - 7 dKH
TDS
80 - 295 ppm
Conductivity
125 - 461 uS/cm
Species description
Geographical Origin and Habitat: Endemic to the Amazon and Orinoco river basins in South America. Prefers fluvial areas with weak to moderate current, abundant with submerged marsh vegetation and dense tangles of branches and roots.
Taxonomy and Morphology: Characin belonging to the Anostomidae family. Reaches 14 cm (5.5 inches). Distinguished by its high, laterally compressed body, with a peculiar and conspicuous sail-like dorsal fin that enhances its oblique head-down swimming (Headstander).
Social Behavior: Schooling animal with strong hierarchical tendencies; keeping single specimens makes them fearful or strangely aggressive. It is imperative to form schools of at least 6-8 individuals to disperse the harmless intraspecific skirmishes for dominance.
Coloration and Sexual Dimorphism: Silvery or pale yellow background crossed by vigorous and faded dark gray or brown vertical bands, irregular and "marbled". The lower fins can show amber or orange reflections. Mature females are distinctly thicker and swollen compared to males.
Care, breeding and tankmates
Aquarium Setup: Long tank (at least 120 cm / 4 feet). Set up with sandy bottoms, huge curved woods and smooth rocks. Warning: it will brutally devour almost every live plant; use only very robust epiphytes (Anubias, Microsorum) tenaciously tied to the woods, or synthetic vegetation.
Diet and Feeding: Tireless vegetarian with omnivorous hints. Requires a massive and continuous vegetable intake: blanched lettuce leaves, zucchini, shelled peas, spirulina and wafers for herbivorous fish. Supplement occasionally with bloodworms and krill.
Water Quality: Robust and adaptable, but demands stability. Temperature 23-27°C (73-81°F), pH tendentially neutral or slightly acidic (6.0 - 7.5), medium hardness (GH 4-15). The water must be excellently filtered but without stormy currents unbearable for its swimming.
Compatibility and Cohabitation: Relatively peaceful with species of similar size and temperament. Excellent companion for large loricariids, peaceful earth-eating cichlids (Geophagus) and generously sized tetras. Avoid slow, timid tankmates or those with long veil fins (it might nip them).
Aquarium Breeding: Extremely rare in captivity. Requires huge tanks, very strong thermal and osmotic shocks simulating the rainy season. They are egg scatterers, do not provide parental care and will greedily feast on their own offspring if not removed.
Risks and Diseases: Very robust; however, if deprived of the vegetable component in the diet it will face lethal intestinal obstructions or nutritional deformations. Suffers acute intoxication in case of sudden spikes in ammonia or nitrites.
Geographic Origin and Distribution
Endemic to the Amazon and Orinoco river basins in South America. Prefers fluvial areas with weak to moderate current, abundant with submerged marsh vegetation and dense tangles of branches and roots.
Origin
Amazon, Orinoco, and Guianas
Fish profile
- Temperament
- No verified data available
- Diet
- No verified data available
- Life expectancy
- No verified data available
- Adult size
- 14 cm
- Sex ratio
- No verified data available
- Feeding frequency
- No verified data available
- Bioload
- Medium
- Flow
- No verified data available
- Jump risk
- No verified data available
- Reproduction
- No verified data available
- Compatibility & tankmates
- No verified data available
- Tank level
- No verified data available
The catalog's scalar value is 14 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 14 cm for this species, recorded as total length (TL). The taxonomic record consulted is Abramites hypselonotus (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
The single-adult profile is classified as medium bioload. The bioload-v2 rubric deterministically assigns this class from the verified maximum length of 14 cm; it is a catalog management category, not a direct measurement of waste output.
Window to the official scientific data of the species
Data synced on: 06/15/2026
Scientific Parameters & Models
- Trophic level
- 2.9 ± 0.33 se
- Resilience
- High (less than 15 months)
- Phylogenetic uniqueness (PD50)
- 0.75
- Bayesian Length-Weight
- a = 0.01072, b = 3.08
VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.
