The Serpae Tetra has a contrasting red-to-black coloring and looks like it has been sprinkled with jewels!

The Serpae Tetra Hyphessobrycon eques is a beautiful fish and really sparkles in the aquarium. A school of these tetras is an eye-catcher. Their beautiful reddish color picks up flashy, jewel-type highlights, and they have a large, almost diamond-shaped black spot just behind the gills.

A number of common names are used to describe this decorative tetra. These include Red Minor Tetra, Jewel Tetra, Callistus Tetra, Red Serpa, Blood Characin, Blood Tetra, and even Red Phantom Tetra. This fish is quickly recognized as a Red Minor Tetra while these other names have more of a story.

This tetra used to be described scientifically as Hyphessobrycon callistus. Today, that is a junior synonym but from it comes the term ‘callistus’ meaning ‘very beautiful.’ So this characin became known as Callistus Tetra. Also from this term, along with its flashy appearance, came the name Jewel Tetra. Another junior synonym, H. serpae, led to the not-so-flashy names Serpae Tetra and Red Serpa. A variety with long fins is usually referred to as Long Fin Red Minor Tetra or Long Finned Serpae Tetra.

The names Blood Tetra and Blood Characin are more curious. These names refer to this tetra’s belonging to a complex of `blood’ tetras. This loosely defined complex refers to a wide range of tetras with a red base body color that are often hybridized for the aquarium trade. Finally, some authors refer to this fish as the Red Phantom Tetra. Be careful not to confuse it with Hyphessobrycon sweglesi, which is more commonly accepted as the Red Phantom.

A school of Serpae Tetra is a real eye-catcher in the aquarium. These fish are also easy to care for. Serpae Tetra are usually fine in a community aquarium, but they are not always easy to get along with. Smaller fish, especially, may become the targets of relentless harassment and fin nipping. Serpae Tetra will do best with the company of their own kind in a school of at least 6. They can also get along fine with other similar-sized and active fish. Once established, they are very hardy, long lived, and easy to breed.

For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Characiformes
  • Family: Characidae
  • Genus: Hyphessobrycon
  • Species: eques
Serpae Tetra – Quick Aquarium Care
  • Aquarist Experience Level: Beginner
  • Size of fish – inches: 1.6 inches (3.99 cm)
  • Minimum Tank Size: 20 gal (76 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Very Hardy
  • Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C)
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Habitat: Distribution / Background

The Serpae Tetra Hyphessobrycon eques (previously Hyphessobrycon callistus) was described by Steindachner in 1882. They are found in South America, particularly in upper Paraguay and the Madeira and Guapore regions. This species is not listed on the IUCN Red List. Other common names they are known by include Red Minor Tetra, Jewel Tetra, Callistus Tetra, Blood Characin, Blood Tetra, Red Serpa, Callistus, and sometimes Red Phantom Tetra. A long-finned Serpae Tetra variety developed in captivity is also called Long Fin Red Minor Tetra.

They frequently inhabit the densely-vegetated and stagnant waters of tributaries, ponds, and small lakes. They stay close to the surface among the plants and feed on worms, crustaceans, insects, and plant matter. They are a gregarious species and live in groups but will frequently bite each other’s fins during feeding.

  • Scientific Name: Hyphessobrycon eques
  • Social Grouping: Groups
  • IUCN Red List: NE – Not Evaluated or not listed


The Serpae Tetra is a deep-bodied fish with the typical tetra shape. Its body is an elongated, laterally compressed oval when viewed from the side.This fish will generally reach about 1 1/2 inches (4 cm) in length and has a lifespan of about 3 to 7 years. The Serpae Tetra has a beautiful, reddish body color that picks up flashy, jewel-type highlights. It has a large, almost diamond-shaped, black spot behind the gills. Their fins are mostly black with white tips. A long-finned variety developed in captivity is usually referred to as Long Finned Serpae Tetra or Long Fin Red Minor Tetra.

  • Size of fish – inches: 1.6 inches (3.99 cm)
  • Lifespan: 7 years – These fish generally have a lifespan of 3 to 7 years, though some have reportedly lived up to 10 years.

Fish Keeping Difficulty

The Serpae Tetra is a very durable fish that is a great choice for the beginning fish keeper. Although these fish are easy to care for, they do have some traits that are less then ideal and can make them a poor choice for tanks with passive inhabitants. These fish can be very boisterous and are known to harass other fish. This, in turn, can stress shy or gentle tankmates.

  • Aquarium Hardiness: Very Hardy
  • Aquarist Experience Level: Beginner – This is an excellent beginner fish as it is both robust and tolerant of a wide range of water conditions.

Foods and Feeding

Since they are omnivorous, Serpae Tetra, or Red Minor Tetra, will generally eat all kinds of live, fresh, and flake foods. To keep a good balance, give them a high quality flake food every day. Feed brine shrimp (either live or frozen) or blood worms as a treat. These tetras like several feedings a day, but offer only what they can consume in 3 minutes or less at each feeding.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet / Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

Serpae Tetras are not exceptionally difficult to care for provided the water is kept clean. Aquariums are closed systems, and regardless of size, all need some maintenance. Over time, decomposing organic matter, nitrates, and phosphate build up, and water hardness increases due to evaporation. To combat these ever-changing conditions, water should be replaced on a regular basis, especially if the tank is densely stocked. At least 25 to 50% of the tank water should be replaced every other week.

  • Water Changes: Bi-weekly

Aquarium Setup

These fish are fairly hardy, and a school of 6 will do best in about a 20-gallon aquarium. Adding aquarium-safe peat to the tank will simulate the black water that these fish inhabit in nature. They need a high quality filter but make sure it does not create too much current as these fish prefer more sluggish waters. Lighting in the tank should be dim as they come from areas that have dense forest cover.

The aquarium should be heavily planted around the sides and back and have plenty of open water for swimming in the front. A few hiding places would be appreciated. Woodwork and floating plants will make them feel comfortable. A biotope tank is preferred by the Serpae Tetra. Use a substrate of river sand, and add scattered driftwood, twisted roots, and a handful of dried leaves to give the tank a natural feel. Make sure to remove and replace the dried leaves every few weeks.

  • Minimum Tank Size: 20 gal (76 L)
  • Suitable for Nano Tank: Yes
  • Substrate Type: Any
  • Lighting Needs: Low – subdued lighting – A tank with a dark, shadowy setup and low lighting will bring out their best coloration.
  • Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C) – deally, they should not be kept below 75.0° F (24° C).
  • Breeding Temperature: 75.0° F – These fish will spawn at 75 to 82° F (24 to 27° C)
  • Range ph: 5.5-7.5
  • Hardness Range: 5 – 20 dGH
  • Brackish: No
  • Water Movement: Moderate
  • Water Region: All – These fish will swim in all areas of the aquarium but will tend to spend a lot of time close to the top if the aquarium has floating plants.

Social Behaviors

The Serpae Tetra can be a good community fish but only if kept with fish that are the same size or bigger. They do best when kept in pairs or in schools of at least 5 to 6 individuals. Groups will make them feel comfortable and help diffuse some of their pugnacious tendencies. If 2 males are kept together, they will act as if they are fighting but will not actually hurt each other.

Smaller fish may become targets for harassment and fin nipping. It is not advisable to keep this fish with slow-swimming, long-finned tankmates. Good choices are similar-sized tetras, rainbowfish, larger rasboras, barbs, and danios. Tetras can be easily spooked into hiding, so situate the tank appropriately.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species – conspecifics: Yes – They do best in a school of 6 or more of their own kind.
    • Peaceful fish (): Safe – This fish may bully smaller and slower-moving fish. Keeping it in a school will make it more comfortable and other fish are less likely to be attacked.
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Monitor
    • Shrimps, Crabs, Snails: Safe – not aggressive
    • Plants: Monitor – May nibble on some aquarium plants.

Sex: Sexual differences

Males are more brightly colored than females, and their dorsal fin is almost solid black. Females lack color in the lower part of the fin. Also, females are fuller-bodied.

Breeding / Reproduction

The Serpae Tetra has been bred in captivity, and a long fin variety has even been developed. They are egg layers and easily bred, making them ideal candidates for the beginning aquarist interested in a breeding project. They reach breeding age at about 8 to 10 months. However, these egg scattering spawners exhibit no parental care. Set up a dedicated breeding tank and remove the parents immediately after spawning, or they will eat the eggs.

Provide a small breeding tank of about 3 to 5 gallons with a dark substrate. Keep the tank dimly lit with bunches of fine-leaved plants, such as Myrophyllum, java moss, or artificial spawning grass, so the female has a place to deposit the eggs. A layer of mesh works, too, if it is wide enough for eggs to pass through but small enough to keep parents out. Floating plants are also helpful to shield the light. Recommended breeding conditions are a temperature of 75 to 82° F (24 to 27° C), pH of 5.5 – 6.8 (6.8 is best), and hardness of 10° dGH. A small, air-powered sponge filter is needed for filtration and gentle water movement.

They can be spawned in pairs or groups containing about the same number of each sex. Condition them with small, live foods. Select a breeding pair or small group and transfer them into the breeding tank in the evening. A mature female’s belly will become nicely rounded when she is full of eggs. Choose males that are the most colorful.

They typically spawn in the early morning, and the females will release about 200 to 300 eggs among the fine-leaved plants. The eggs will hatch in approximately 24 to 28 hours, and the fry will be free-swimming a few days later. For the first few days, feed the fry infusoria-type foods until they can feed on microworm or brine shrimp nauplii. See Breeding Freshwater Fish: Characins for a general description of breeding processes, and see Fish Food for Fry for information about types of foods for raising the young.

  • Ease of Breeding: Easy

Fish Diseases

The Serpae Tetra is very hardy, and disease is not usually a problem in a well-maintained aquarium. That being said, there is no guarantee that you won’t have to deal with health problems or disease. Anything you add to your tank can introduce disease. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so as not to upset the balance.

A good thing about Serpae Tetra is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if dealt with at an early stage. When keeping more sensitive types of fish, it is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to give your Serpae Tetra the proper environment and a well-balanced diet. The more closely their environment resembles their natural habitat, the less stress the fish will have, making them healthier and happier. Stressed fish are more likely to acquire disease.

As with most fish, they are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. Aquarists should read up on common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Serpae Tetra, or Red Minor Tetra, is readily available in pet stores and online and is reasonably priced. A long-finned variety that was developed in captivity is often available. This variety is usually referred to as Long Fin Red Minor Tetra or Long Finned Serpae Tetra.