Serpae Tetra Longfin - Hyphessobrycon callstusi

Longfin Serpae Tetra (Megalamphodus eques)

The Longfin Serpae Tetra is a colourful captive-bred fin form of the classic Serpae Tetra, loved for its rich red to scarlet body colour, dark shoulder marking and extended flowing fins. Also known as the Longfin Red Minor Tetra or Longfin Jewel Tetra, this active South American tetra is best kept in a proper group where its natural shoaling behaviour can be seen. It is hardy and attractive, but it can be fin-nippy if kept in small numbers, so it is best suited to a robust community aquarium rather than a delicate long-finned setup.

Common Name:
Longfin Serpae Tetra. Also commonly referred to as Serpae Tetra Longfin, Longfin Red Minor Tetra, Longfin Jewel Tetra, Red Minor Tetra, Blood Characin or Callistus Tetra.

Scientific Name (Latin):
Megalamphodus eques
Still widely referenced in the aquarium trade as Hyphessobrycon eques. Older synonyms include Hyphessobrycon callistus and Hyphessobrycon serpae.

Maximum Size:
Around 4–5 cm in captivity, with the longfin variety appearing larger due to the extended finnage.

Water Type:
Freshwater

Origin / Natural Habitat:
The Longfin Serpae Tetra is a captive-bred aquarium strain. The wild Serpae Tetra is native to South America, including the Amazon, Guaporé and Paraguay River basins. In nature, it is associated with slow-moving or stagnant freshwater habitats, especially areas with emergent plants, vegetation and cover near the surface.

Water Parameters:
Temperature: 22–26°C
pH Range: 5.5–7.8
Hardness: soft to moderately hard water

Temperament:
Semi-aggressive. Serpae Tetras are active, social and can be fin-nippy, especially if kept in too small a group or with slow, long-finned tank mates. They are best kept in good numbers so their energy and hierarchy remain mostly within the shoal.

Diet:
Omnivorous. In the wild, Serpae Tetras feed on worms, small crustaceans, insects and plant matter. In the aquarium they should be offered a varied diet including quality flake, micro pellets, small granules, frozen daphnia, brineshrimp, cyclops, bloodworm and occasional live foods.

Minimum Tank Size:
A practical recommendation is at least 80–100 litres for a proper group, with a 75–90 cm aquarium or larger preferred due to their active behaviour and need for swimming space.

Behaviour & Activity:
This is an active mid-to-upper level shoaling tetra that should be kept in a group of at least 8, ideally 10 or more. In good numbers, Longfin Serpae Tetras are more confident, display better colour and are less likely to target other fish. They appreciate planted edges, shaded areas, open swimming space and a secure lid, as active tetras may jump when startled.

Aquarium Category:
Semi-Aggressive
This species can work well in a robust community aquarium, but it should not be treated as a gentle nano tetra. Suitable tank mates include other active tetras, danios, peaceful barbs, rainbowfish, Corydoras, bristlenose plecos and confident community fish of similar size. Avoid bettas, fancy guppies, long-finned fish, very timid nano species, slow gouramis, angelfish with trailing fins and delicate fish that may be stressed by constant activity.

Special Requirements or Care Notes:
Best kept in a mature, well-filtered aquarium with clean water, stable parameters and regular maintenance. Group size is very important with Serpae Tetras, as small groups are much more likely to become nippy or disruptive. Because this is a longfin strain, avoid sharp décor and any tank mates likely to nip fins. Darker substrate, plants and a varied diet will help bring out stronger red colouration.

Suitable for:
Beginner to intermediate fishkeepers

Availability:
Common / occasional in trade, usually as captive-bred stock

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.