Serpae Tetra Tank Requirements: Ideal Habitat Simplified

The serpae tetra (lat. Hyphessobrycon eques) is a tropical freshwater species which are sometimes referred to as red tetra. This is an overwhelmingly beautiful fish that looks like a small moving flame in a tank. You won’t be able to take your eyes of tetras school in an aquarium.

Habitat in the wild

The serpae tetra, scientific name Hyphessobrycon eques, belongs to the family Characidae. The Characidae family is one of the largest and most diverse families of freshwater fish, commonly known as characids or characins. It includes a wide variety of fish species, many of which are popular among aquarium hobbyists due to their vibrant colors, peaceful nature, and active behavior.

Serpae tetras are native to South America, specifically found in the Orinoco and Amazon River basins, as well as the Guyana Shield. You may encounter quite a lot of these fishes in the waters from Guyana to the river Paraguay in Brazil, in Guiana. The serpae tetra is rather spread one, it inhabits in impounded waters with lots of plants: tributaries, ponds, small lakes, prefer to stay close to water surface where they feed on insects, their larva and parts of plants.

In the wild, they inhabit slow-moving or still waters, such as streams, rivers, and flooded areas with dense vegetation. Their natural habitat consists of heavily vegetated areas with submerged plants, driftwood, and leaf litter, which provide them with ample hiding places and territories.

Water conditions in their natural habitat can vary, but they generally prefer soft to moderately hard water with a slightly acidic to neutral pH. The temperature in their native environment usually ranges from 72°F to 82°F (22°C to 28°C).

Serpae tetras are shoaling fish, meaning they prefer to live in groups and feel more secure and less stressed when surrounded by conspecifics. In their natural habitat, they form schools with other tetras for safety and foraging purposes.



Serpae tetras are relatively small fish. As adults, they typically reach a size of about 1 to 1.5 inches (2.5 to 3.8 centimeters) in length. This measurement includes their body from the tip of the snout to the base of the tail fin. Their small size makes them suitable for a wide range of aquarium setups and allows them to thrive in community tanks with other small, peaceful fish.


The average lifespan of serpae tetras is typically around 3 to 5 years. However, with proper care and a suitable environment, some individuals might live slightly longer, while others may have a shorter lifespan.

The lifespan of any fish can be influenced by various factors, including water quality, diet, tank size, stress levels, and genetics. To help ensure the health and longevity of your serpae tetras, it’s essential to provide them with a well-maintained aquarium, appropriate water parameters, a balanced diet, and companionship with their own species (preferably in a group of at least six individuals).


The back is olive-brown and its sides are red, there is a small black spot on the opercle (sometimes it’s missing). The dorsal is black (sometimes it has white edges or only the ending). The rest of the fins are bloody red, all except the flesh fin.

Scientific NameHyphessobrycon eques
Common NameSerpae Tetra; red tetra; red minor tetra; callistus tetra
Native RegionSouth America (Orinoco and Amazon basins)
Adult SizeUp to 1.5 inches (3.8 cm)
Lifespan3 to 5 years
BehaviorShoaling, generally peaceful but can be semi-aggressive towards similar-looking species
TemperamentPeaceful with proper tankmates, avoid keeping with long-finned or slow-moving fish
ColorationVibrant red with a black spot near the caudal fin
Tank SizeMinimum 20 gallons for a small group
Water ParametersTemperature: 72°F to 82°F (22°C to 28°C)
pH: 6.0 to 7.5
Hardness: Soft to moderately hard
DietOmnivorous – High-quality flakes, pellets, and occasional live or frozen foods
HabitatSlow-moving or still waters with dense vegetation, submerged plants, driftwood, and leaf litter
Tank SetupHeavily planted with hiding spots and open swimming areas, dark substrate, and driftwood
Schooling BehaviorPrefers to live in groups of at least six for security and stress reduction
CompatibilitySuitable for community aquariums with peaceful tankmates of similar size
BreedingEgg-scattering species, separate adults after spawning to protect eggs and fry
Special ConsiderationsAvoid keeping with fin-nipping or aggressive tankmates, provide good water quality and perform regular water changes

Difficulties in keeping

Serpae tetra care isn’t difficult since the fish isn’t a demanding one.

It lives in small tanks and it’s not a fish that is hard to be kept in aquarium. Although the serpae tetra is easy in care it can become a problem itself when chasing and nipping the fins of slow tank mates. Because of that you should be careful when choosing tetra tank mates.

This is a schooling fish and it feels better in a school. There should be at least 6 fishes in it and the fish can be kept together with some other fishes of the same size and activity level. The drawback of keeping tetras in a tank is their a bit troublesome temper – they can haunt and nip the fins of more slow tank mates.

Care and keeping in a tank

Tank size

The recommended tank size for a group of serpae tetras (Hyphessobrycon eques) is a minimum of 20 gallons (about 75 liters). These fish are active and enjoy swimming, so providing them with enough space is important for their well-being and overall health. Keeping them in a larger tank is even better as it allows for more swimming room and provides a more stable environment with easier maintenance.

When keeping serpae tetras, it’s crucial to remember that they are schooling fish. They feel more secure and less stressed when kept in a group of at least six individuals or more. So, while a 20-gallon tank can accommodate a small group of these tetras, if you plan to keep a larger school, you should consider a larger tank accordingly. A school of serpae tetras swims in the middle or bottom water layer in a tank. You can keep these fishes in a community tank (more than 60 cm (24 in) long) together with rather active tank mates.

Additionally, having a well-planted aquarium with hiding spots and open swimming areas is beneficial for serpae tetras, as it replicates their natural environment and provides them with places to explore and seek refuge when needed.

Water parameters

Optimal water parameters for keeping are the following:

  1. Temperature: 72°F to 82°F (22°C to 28°C)
    Serpae tetras are comfortable in a tropical aquarium with temperatures within this range.
  2. pH Level: 6.0 to 7.5
    These tetras prefer slightly acidic to neutral water conditions. It’s essential to keep the pH stable within this range.
  3. Water Hardness: Soft to Moderately Hard
    Serpae Tetras can tolerate a range of water hardness levels. Aim for a general hardness (GH) of 4 to 12 dGH and carbonate hardness (KH) of 2 to 8 dKH.
  4. Ammonia, Nitrite, and Nitrate: Low to Non-detectable levels
    Ammonia and nitrite should always be at 0 ppm (parts per million) since they are toxic to fish. Nitrate should be kept as low as possible, preferably below 20 ppm, through regular water changes.
  5. Filtration and Aeration:
    A good filtration system is essential to maintain water quality by removing waste and toxins. Adequate aeration and water movement also help provide oxygen to the fish and maintain stable water conditions.

Remember that sudden and drastic changes in water parameters can stress fish and lead to health problems. When performing water changes, try to match the new water’s temperature and parameters as closely as possible to the existing aquarium water.

Regular water testing and monitoring are vital to ensure the water parameters remain within acceptable ranges. Adjustments can be made as needed to create an optimal environment for your serpae tetras and other tank inhabitants.


Serpae tetras are omnivorous fish, which means they eat a varied diet consisting of both animal and plant matter. In the wild, they feed on small insects, crustaceans, plant material, and algae. To keep them healthy and vibrant in an aquarium, it’s essential to replicate their natural diet as closely as possible. Keep in mind that this tetra has a small mouth, so you have to choose small grained types of feed.

Here are some suitable foods for a balanced serpae tetra diet:

  1. High-quality Flakes or Pellets: Commercial fish flakes or pellets formulated for tropical fish are a good staple diet for serpae tetras. Look for products that contain a mix of protein sources and essential vitamins and minerals.
  2. Live or Frozen Foods: Offer live or frozen foods like brine shrimp, daphnia, bloodworms, and mosquito larvae as occasional treats. These foods provide essential nutrients and mimic the type of protein-rich diet they would find in the wild.
  3. Vegetable Matter: Serpae tetras also consume plant material, so you can supplement their diet with blanched vegetables such as spinach, zucchini, or peas. These vegetables should be softened and chopped into small pieces to make them easier for the tetras to eat.
  4. Algae-based Foods: Spirulina-based flakes or pellets can be included in their diet to satisfy their herbivorous tendencies and provide additional nutrients.

It’s essential to feed serpae tetras a varied diet to ensure they receive all the necessary nutrients for optimal health and coloration. Overfeeding should be avoided as it can lead to water quality issues. Offer an amount of food that the fish can consume within a few minutes and remove any uneaten food promptly.

Tank mates

Serpae tetra is considered to be a proper fish to keep in community tanks, but it’s not exactly so. It’s true only if the neighbors with large and active fishes. The fishes that are smaller than tetra will be haunted and pressured.

The same is about any slow fishes with large fins, for example bettas or angelfish – their long fins will be constantly nipped, till the fish gets sick or dies. Therefore, it’s crucial to choose tank mates that can coexist peacefully with serpae tetras and are not overly sensitive to fin nipping.

However, if serpae tetra is in a school, its temper becomes more calm regarding other fishes in a tank, since they have an hierarchy inside the school and the focus of the fish attention gets shifted onto their family. At that males pretend to fight with each other, however they don’t do any harm to each other.

Here are some suitable tank mates that are generally compatible with serpae tetras:

Gender differences: male vs female

It’s rather difficult to see between serpae tetra male and female. The difference between them is shown more before the spawning. However, there are some subtle differences that can help you determine their sex:

  1. Body Shape: In general, female serpae tetras tend to have a slightly rounder and fuller body compared to males. This difference may become more evident as the fish mature.
  2. Color Intensity: Female serpae tetras often have less intense coloration compared to males, particularly when it comes to their red coloration. Male serpae tetras usually display deeper and more vibrant red hues.
  3. Fin Size and Shape: Males may have more extended and pointed dorsal and anal fins compared to females, especially during the breeding season. Female fins are generally more rounded and shorter.
  4. Behavior: During the breeding period, male serpae tetras may exhibit more pronounced chasing and courtship behaviors, while females might be seen seeking out places to deposit their eggs.

It’s important to note that these differences might not be extremely noticeable, and it can be challenging to determine the sex of young or immature serpae tetras. The most reliable method of sexing serpae tetras is by observing their behavior during the breeding season or looking for obvious physical changes as they reach sexual maturity.


Serpae tetra becomes reproductive at the age of 8-10 month. You’ll need a separate spawning tank with the square of its bottom at least 700 cm², a protective grid and a bush of some small plants in the middle of a tank.

The lights should be dim and soft. Water temperature should be within 24—28 °C, general water hardness not more than 6°, carbonate hardness — not more than 1°, acidity 6—6,8. The water layer should be about 12—15 cm high. It’s recommended to use water with some turf in it.

The mixture can be prepared the following way: concentrated decoction of turf is added into defecated water, at the same time pH value is being controlled and then the water should be settled for a week (sometimes for a month).

After that 2/3 of the water volume is poured into the spawning tank, however some fresh water can also be used. Take a serpae tetra female with rounded abdomen and 2 male or a couple and put them into the tank in the evening, at the same time make the water temperature higher.

Quite often breeding starts before the sunrise and it finishes right when the sun is up. Feed the fishes with some blood worms 72 hours later. About 200-300 grayish eggs laid by the female get stuck on the tank plant leaves or fall on the tank bottom.

The tank plants and protective grid are remover from the tank after the spawning. The tank should be shaded then to protect the eggs from direct light. Some soft aeration is required.

You shouldn’t touch the eggs, its very sensitive to this. Juveniles hatch in 24-30 hours after the spawning and they start swimming in several days (3-5 days). During this time interval you can switch on the aeration and the lights in the tank. Start feed for juveniles is rotifers, infusorians.