Hyphessobrycon eques (serpae tetra)

Hyphessobrycon eques or the Serpae tetra belongs to the Characidae family and Characiformes order. The species may also be known as Hyphessobrycon serpae and Hyphessobrycon callistus. Other common names of the species are the jewel, red minor, Blood, and Callistus tetra.
The species is native to South America (Amazon drainage and Rio Paraguay in Brazil,). The Serpae tetra occurs in still and slow-moving waters with thick vegetation and submerged tree roots. Furthermore, the Serpae tetra inhibits in tributaries, the margins of lakes and ponds. The water conditions are low in minerals and nutrients and rich in tannins due to the decomposition of organic matter such as woods and leaves (an indication of soft and acidic habitat). Most of the specimens in the aquarium industry bred in fish farms.
Serpae tetra has a flat body with a light-red to dark-red color. Some individuals may have a dark band behind the gills. As the fish ages, there is a chance the dark spot disappears and the red color fades. Usually, the dorsal fin is black while the other fins are red. There are two varieties of Serpae tetra, the standard and the long fin variety due to selective breeding. Furthermore, male Serpae tetras are thinner and more colorful while mature female Serpae tetras have round abdomens. The species grow up to 4,5 cm and have a lifespan of 4 years.
Serpae tetras are hardy fish and easy to maintain which makes them a good choice for beginners. Furthermore, the species are easy to breed. Like all the tetras, Hyphessobrycon eques is a shoaling fish that should be kept in groups of 8 individuals (minimum) and more. However, a bigger shoal of Serpae tetras is more suitable. Serpae tetras are one of those tetras that need a group but don’t always actively school together. This behavior indicates that they feel safe. They sometimes shoal when they are stressed.
Serpae tetras are famous for their aggression (nibbling the tails of fish) to different species and sometimes to smaller Serpae tetras. They bully one another as they form a hierarchy. You can reduce their aggression by keeping them in bigger shoals, in bigger tanks with thick vegetation and many hiding spots. When you buy new individuals is preferable to have a similar size with the Serpae tetras you already have and is normal for a few days the old Serpae tetras to bully the new Serpae tetra to form a new hierarchy.
It’s best to keep the species in an only-species tank. However, if you choose a community tank, some compatible species with Serpae tetras are barbs, danios, larger tetras, corydoras, etc. However, fishes can be unpredictable sometimes, so I recommend you keep an eye on Serpae tetras, especially if you choose to put them in a community tank.
Because of the natural habitat of the Serpae tetra should be kept in soft acidic water. You may decorate the aquarium with, rocks, leaves, and woods and many plants to create hiding spots. Furthermore, they need plenty of space to swim freely. A pH between 5.0-7.5 with the ideal being about 6.8 pH, with a temperature between 22-26 Celsius, and hardness between 5-20 dGH, suits the species. An aquarium of 80 liters could be enough for a group of 8-10 Serpae tetras.
Serpae tetras are omnivorous and can eat prepared food and small live-foods. In nature, their diet consists of crustaceans, insects’ larvae, worms, and plant matter, e.t.c.
Several tetra species are difficult to reproduce but that is not the case with Serpae tetras that spawn better at 26-27 Celcius and 6,0-6,5 pH. Furthermore, you may cover the tank to create darkness with papers or other materials because tetras’ eggs and fry are sensitive to daylight. After twelve days the young are not susceptible to the light. A mixed diet with live food prior spawning attempt may help. Woods and leaves (almond leaves) benefit the process as they provide tannins and humic acids. The tank needs good aeration for the optimal health of the eggs. An air-powered sponge filter does the work. You may use a breeding tank of 40 liters (10 gallons) for better results for a pair or three females with three males in the tank.
Usually, the spawn begins the next day and lasts for 3-4 hours. Replace the individuals if no eggs have appeared for 2-3 days. Remove the adults If the spawning is successful to protect the eggs. Furthermore, you may cover the bottom of the tank with a net to protect the eggs from the adults. The female lays up to 200 eggs, which hatch in about 24 hours. Keep in mind that the temperature affects the eggs’ hatching period. For 3-5 days the young feed on the yolk sac, so in that period they don’t need food. After the consumption of the yolk sac, you can feed the young three times per day with newly hatched brine shrimp, infusoria, daphnia, crushed flake food, etc.

Long Finned Serpae Tetra Barb Hyphessobrycon eques aquarium fish
“iStock.com/ Mirko Rosenau”


  1. Hyphessobrycon eques. Retrieved from: https://www.seriouslyfish.com/species/hyphessobrycon-eques/
  2. Brian Cole and Michael Haring 1999, Spawning and Production of the Serpae Tetra, Hyphessobrycon serpae. Retrieved from: http://www.ctsa.org/files/publications/CTSA_1386316728568618675601.pdf
  3. Hyphessobrycon eques TSN 639869. Retrieved from: https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=639869#null

How useful was this post?

Click on a star to rate it!

Average rating / 5. Vote count:

Leave a Reply

Your email address will not be published. Required fields are marked *