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Serpae Tetra

Hyphessobrycon eques


Serpae tetra

Long-finned Serpae tetra

Luke Underwood
Hyphessobrycon eques - Serpae Tetra

Male Serpae Tetra

Joel Bez
Hyphessobrycon eques - Serpae Tetra

Female Serpae Tetra

Joel Bez
  • Scientific Name: Hyphessobrycon eques
  • Synonym: Cheirodon eques, Chirodon eques, Hemigrammus melasopterus, Hemigrammus serpae, Hyphessobrycon callistus, Hyphessobrycon serpae, Megalamphodus eques, Tetragonopterus callistus
  • Common Name: Blood Characin, Callistus, Callistus Tetra, Jewel Tetra, Red Minor Tetra, Red Serpae, Serpa Tetra, Serpae Tetra
  • Family: Characidae
  • Origin: Brazil and Paraguay
  • Adult Size: 1.75 inches (4.5 cm)
  • Social: Peaceful schooling fish
  • Lifespan: 5 years
  • Tank Level: Mid dweller
  • Minimum Tank Size: 20 gallons
  • Diet: Omnivore, enjoys live foods
  • Breeding: Egglayer
  • Care: Easy
  • pH: 5.0-7.8
  • Hardness: 5-25 dGH
  • Temperature: 72-79 F (22-26 C)



Serpae Tetras originate from the Amazon basin, inhabiting the Guaporé and Paraguay River basins in Argentina, Brazil and upper Paraguay. Most specimens currently sold in the aquarium trade are captive bred rather than wild caught.

This species is part of a group known as “Blood Tetras”, referring to their red coloration. Considerable confusion and debate has continued over species within this group, as they have strong similarities. Study of the taxonomic status of this and similar species continues.

Currently this species is known by the scientific name of Hyphessobrycon eques, but has also been known as; Cheirodon eques, Chirodon eques, Hemigrammus melasopterus, Hemigrammus serpae, Hyphessobrycon callistus, Hyphessobrycon serpae, Megalamphodus eques, and Tetragonopterus callistus. Serpae Tetras are also known by the common names of; Blood Characin, Callistus, Callistus Tetra, Jewel Tetra, Red Minor Tetra, Red Serpae, and Serpa Tetra.


The deep red color of the Serpae Tetra is a large part of what makes it so popular. Reaching an adult size of about one and three quarters inch, they body of the Serpae is flat and tall. A black comma-shaped spot is present just behind the gills. The dorsal fin is predominantly black, edged with white. All other fins are red, with the anal fin being edged in black with a splash of white a the leading tip. As the fish ages, these colors fade, particularly the spot behind the gills.

When kept in a school, they are generally peaceful. However, they have been known to nip fins, a behavior that is most often directed as its own kind, and more prevalent during feeding times. Females are plumper and less brilliantly colored than their male counterparts. Long-finned variations have been produced.


Generally considered a peaceful fish, the Serpae Tetra should always be kept in schools of a half dozen or more. Ideal tankmates are other active fish of similar or larger size, such as Barbs, Danios, and larger Tetras. Bottom dwelling catfish and loaches are also suitable tankmates. Avoid keeping this species with fish that have long flowing fins, or are slow moving, such as Angelfish or Bettas. Also avoid keeping them with smaller species of fish, as they may harass them. Serpae Tetras are most likely to show aggression at feeding time. Placing food at several locations, or using multiple feeding rings, can help reduce nipping at feeding time.


Easy to care for, the Serpae Tetra is most at home in an Amazon habitat. In nature this fish is accustomed do quiet waters with roots and organic debris. The use of peat or blackwater extract will help mimic this type of soft, acid water.

A dark substrate is best, with somewhat subdued lighting. Leave an open swimming space, with driftwood, plants, and other décor around the edges to provide hiding places. Keep the water movement slow within the tank. They are not recommended for a newly set up tank, as they are somewhat sensitive to changes in water parameters.


In their natural environment, Serpae Tetras eat small live foods, such as insects, invertebrates and worms. In the aquarium they will accept virtually any food quite readily, including flake, pellet, freeze-dried and frozen foods. To keep them in prime condition, and bring out their colors, feed a good variety of food types, including live foods when available.

Sexual Differences

Differences between the sexes are slight, and are most apparent when ready to spawn. Males are more brightly colored, slimmer and the dorsal fin fully black. In females the dorsal is paler. Females are fuller in the body, even when not spawning.


Serpae Tetras are relatively easy to breed. They can be bred as pairs, or in groups of roughly an equal number of males and females. The key to successful breeding is to set up a tank with the proper habitat for spawning and subsequent grow-out of the fry.

Set up a small tank with dark substrate, very dim lighting, and spawning mops or fine-leaved plants, such as Java Moss or Myriophyllum. The water should be very soft, no more than 6 to 8 dGH, and pH approximately 6.0. Provide gentle filtration, such as an air-driven sponge filter. Keep the water around 80 F (27 C).

Condition the spawning pair with a variety of foods, including live foods if possible. Males will become more colorful and females will become noticeably plump when ready to spawn. Eggs will be scattered over the plants or spawning mop. Once the eggs have be laid, the adults should be removed, as they will consume the eggs. Turn off all lighting in the tank, as the eggs are highly sensitive to light.

In one to two days the eggs will hatch, after which they will feed on their yolk sack for several days. Once they are free swimming, they will feed on infusoria and freshly hatched bring shrimp. Finely crushed flake foods or commercially prepared fry foods can also be provided in lieu of brine.

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