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Maximum size : 3 cm

Brittanichthys Axelrodi Tetra - Brittanichthys axelrodi : Complete Fish Profile & Care Guide

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Although its exact taxonomic position remains a mystery, the enigmatic Brittanichthys Axelrodi Tetra (Brittanichthys axelrodi) captivates aquarists with its small, delicate nature and peaceful demeanour. This rare gem, often unseen in the hobby, adds a touch of elegance to nano aquariums or well-planted setups. While they thrive among their own kind, these Tetras can coexist harmoniously with small, peaceful species in a spacious community aquarium. Occasionally, males may display territorial behaviour towards each other, but rest assured, no actual harm will befall them.

The Brittanichthys axelrodi Tetra hails from the depths of blackwater ecosystems, evoking an alluring ambience. Filtering the water through peat improves chemical parameters and harnesses peat's bactericidal properties, reducing the bacterial load within the aquarium. To recreate the mystique of their natural habitat, consider adorning the aquarium with dried leaves like Indian almond or oak alongside driftwood and alder cones. Then, as the water gradually darkens, a captivating resemblance to their native waters will unfold.

Although the information on the Brittanichthys axelrodi Tetra is currently scarce, their transparent bodies and fins lend an ethereal quality to their appearance. A striking red stripe gracefully adorns their caudal fin, extending along half of the posterior part of their body. Completing their mesmerizing allure, a thin black line elegantly traces the dorsal fin's top edge. As keepers of these Tetras observe their subtle nuances, they become part of an ongoing journey of discovery and appreciation for this remarkable species.

Brittanichthys Axelrodi Tetra Photos

Sexual Dimorphism

Distinguishing between the male and female Brittanichthys Axelrodi Tetra can be achieved with relative ease. Males exhibit a striking display of vibrant colours, showcasing their unique beauty. Furthermore, mature males possess distinct bony hooks on their anal fin, along with a gracefully curved caudal fin. Conversely, females display more subdued stripes in comparison to their male counterparts, lacking the characteristic bony hooks. This notable sexual dimorphism allows for a clear differentiation between the two sexes of this fascinating species.

Quick Facts

Scientific NameBrittanichthys axelrodi
Year Described1965
Other NamesNone
OriginsBrazil Colombia
Max Size3 cm
Aquarium LevelMiddle - Top
Best kept asGroups 8+
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
PH4.0 - 7.0
GH1 - 5
KH2 - 6
TDS20 - 215
76 - 82
24 - 27

Natural Habitat

The mesmerizing Brittanichthys Axelrodi Tetras can be found exclusively in the enchanting Rio Urubani, Rio Demini, and Rio Muco within the sprawling Rio Negro Basin of Brazil and Colombia in South America. These remarkable Tetras call the soft, acidic, and crystal-clear blackwater rivers and streams their home, where the underwater landscape is adorned with a tapestry of leaf litter and the intricate interplay of driftwood roots and branches. Their natural habitat provides the perfect haven for these captivating fish to thrive and exhibit their unique behaviours and exquisite beauty.


The reproductive behaviour of the Brittanichthys Axelrodi Tetra remains shrouded in mystery, as our understanding of their breeding habits is currently limited. Intriguingly, studies suggest that the males employ an unusual method of inseminating females with sperm, deviating from the external fertilization typically observed in most Tetras. Regrettably, reports of successful spawning in captivity are scarce, adding to the enigmatic nature of these captivating fish. While their reproduction may elude us for now, their elusive nature invites further exploration and scientific inquiry to unlock the secrets of their breeding behaviour.

Diet & feeding

Brittanichthys Axelrodi Tetras exhibit a versatile and adaptable feeding behaviour, readily accepting a wide range of aquarium foods. During their initial introduction to the aquarium, these Tetras may display some shyness towards food, hence it is recommended to provide them with live food as an enticing stimulus. Once acclimated and settled in their new environment, a well-rounded and balanced diet should consist of premium-quality dried foods such as flakes, pellets, and granules. Enhance their diet by supplementing it with the inclusion of frozen and live foods like brine shrimp, daphnia, Tubifex, and bloodworms, which offer essential nutrients and natural variety. Additionally, occasionally including green vegetables in their diet will contribute to their overall health and vibrant colouration, ensuring optimal well-being for your prized specimens.

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