Bloodfin Tetra Care Guide - Aquarium Setup, Diet & Breeding

The Bloodfin Tetra is a lively, streamlined schooling fish named for the vivid red colouring in its tail and the rear portions of its dorsal and anal fins. Its silvery body often reflects blue, green or gold tones as it moves through the aquarium, making the red fins especially striking against darker surroundings.

This species is active and constantly on the move, spending much of its time in the middle and upper levels of the water. Bloodfin Tetras are generally peaceful, but they can be energetic and may occasionally nip at the fins of slow-moving or long-finned fish when kept in an undersized group.

In the wild, they occur in flowing and quiet waters associated with larger river systems, including tributaries, seasonal floodplain habitats and vegetated margins. Their natural environment can vary in water chemistry and flow, helping explain their reputation as adaptable community fish.

Bloodfin Tetras are social by nature and display their best behaviour when kept in a proper shoal. In a group, they spend more time exploring and may perform brief displays and energetic chases without causing serious harm to one another.

Bloodfin Tetras are native to the subtropical freshwater rivers, streams and floodplain waters of southern South America, particularly in Argentina, Paraguay and parts of Uruguay. They inhabit the Paraná and Uruguay river systems and nearby tributaries.

A group of Bloodfin Tetras should have at least a 75-litre aquarium, with a tank around 90 cm long preferred because these active swimmers benefit more from horizontal space than from height. Use open swimming areas alongside dense planting, driftwood and shaded sections that provide cover without cluttering the central swimming zone. A dark, fine-grained substrate can bring out their colours, although smooth sand or fine gravel is suitable. Secure filtration, good oxygenation and a gentle to moderate current replicate the well-oxygenated waters they inhabit.

Up to 5.5 cm (2.2 in) in total length. Females are usually slightly larger and deeper-bodied than males.

Bloodfin Tetras are omnivores and readily accept quality tropical flakes, micro-pellets and granules. For a varied diet, supplement these foods with frozen or live daphnia, mosquito larvae, brine shrimp and bloodworms. Small portions offered regularly help maintain their condition and enhance their natural colour, while suitably fine foods are important for younger fish.

Bloodfin Tetras suit peaceful community aquariums containing similarly sized, active fish. Good companions include other robust tetras, larger rasboras, danios, peaceful barbs, Corydoras, small plecos and non-aggressive dwarf cichlids. Avoid housing them with very slow, timid or long-finned fish such as bettas, fancy guppies and long-finned gouramis, as their occasional fin-nipping and constant activity may cause stress. They should also be kept away from predatory fish large enough to swallow them.

Bloodfin Tetras are egg-scattering spawners that can be bred in a separate, dimly lit breeding aquarium with soft water and fine-leaved plants or spawning mops. Condition the adults with plenty of small live or frozen foods, then introduce a pair or small group. Spawning usually takes place among the plants, after which the adults should be removed because they may eat the eggs. The eggs generally hatch within about 24 to 36 hours, and the tiny fry initially need infusoria or another suitably fine first food before progressing to baby brine shrimp.

Females tend to have a fuller, rounder abdomen, especially when carrying eggs, while males are generally slimmer. Mature males may show slightly more extended fins and a more intense red coloration, although the differences can be subtle.