Redfin Penguin Tetra Care Guide - Aquarium Setup, Diet & Breeding

The Redfin Penguin Tetra is a graceful, active characin with a silvery body, a dark horizontal stripe and distinctive red colouring in the fins. Like other penguin tetras, it often swims with the head slightly raised and the tail angled down, creating its characteristic tilted posture. The contrast between the bright fins and dark markings makes this fish especially attractive in a planted aquarium.

This fish is sociable and alert, spending much of its time moving through the middle and upper levels of the aquarium. It is generally peaceful, but individuals can become withdrawn when kept alone or in very small numbers. In a proper group, they display more natural confidence and frequently form loose shoals while exploring their surroundings.

In the wild, it is associated with tributaries and forested waterways where overhanging vegetation, submerged branches and leaf litter provide cover. These habitats can contain clear to lightly tea-coloured water, with gentle flow and areas of shade. The species' streamlined shape and unusual swimming angle are well suited to navigating among branches and marginal plants.

Thayeria sp. Rio Teles Pires is traded as a regional Redfin Penguin Tetra and is not always given a formally established species name in the aquarium trade. It is related to the better-known penguin tetras of the genus Thayeria, but its red fins and locality identity make it a distinctive choice for South American community aquariums.

Thayeria sp. Rio Teles Pires comes from the Rio Teles Pires basin in Brazil, part of the upper Tapajós drainage in South America. It inhabits warm, slow-moving forest streams and tributaries associated with the Amazon basin.

A group of Redfin Penguin Tetras should have at least 80 litres, with a tank around 90 cm long preferred so they have room to swim. Use a gentle to moderate current, a secure lid and stable, well-filtered water. A dark sand or fine-gravel substrate, dense planting around the sides and rear, floating plants, driftwood and shaded open swimming areas create a natural-looking setup. Leaf litter can be added where appropriate, provided it is clean and replaced as it breaks down.

Up to 5 cm (2 inches) in adult length. Females are often slightly deeper-bodied than males, particularly when carrying eggs.

This omnivorous species accepts quality small flake, micro-pellets and granules, but it benefits from regular variety. Offer frozen or live foods such as brine shrimp, daphnia, mosquito larvae and bloodworm in appropriately small portions. Feeding little and often helps maintain condition, supports colour and allows all members of the shoal to eat without excessive competition.

Redfin Penguin Tetras are peaceful community fish and can be kept with similarly sized tetras, peaceful rasboras, pencilfish, small peaceful barbs, Corydoras, otocinclus and other calm South American community species. They are best kept away from large, aggressive or highly predatory fish, fin-nipping species and boisterous tankmates that may intimidate them or damage their fins. Shrimp shrimplets and very small fry may be eaten, although adult ornamental shrimp are usually left alone.

Redfin Penguin Tetras are egg-scattering fish that can be bred in a separate, dimly lit aquarium with soft, slightly acidic water and fine-leaved plants or spawning mops. Condition a group with plenty of live or frozen foods, then introduce well-matched adults. Spawning usually takes place among the plants, after which the adults should be removed because they may eat the eggs. The eggs typically hatch within a day or two, and the tiny fry need infusoria or another suitably fine first food before moving on to newly hatched brine shrimp.

Females are usually a little fuller through the abdomen and deeper-bodied than males, while males tend to be slimmer. Differences can be subtle outside breeding condition, and the red fin colour is not a reliable way to sex them.