Posted on

Serpae Tetra: the red arrow

The Serpae Tetra receives a variety of names that are related to its beautiful color. The species stands out among other tetras for the intensity and contrast of its colors. It is a very lively fish to keep in schools in planted aquariums. Nothing being seen between the middle zone and the surface of the aquarium.

The importance of properly differentiating it from other species of the same family must be pointed out, since its behavior is not necessarily peaceful, as one would expect from most tetras. Its character is described as moderate aggressiveness and with a clear tendency to peck the fins of other specimens of the same species, or of any other aquarium fish with delicate fins. It definitely may not be a good tank mate for smaller guppies or tetras, and this behavior has also been known towards even larger fish like betta splendens or gouramis.

Their aggressive behavior is revealed when we feed them. They are very lively swimmers that will quickly ingest food and – at the same time – have an inclination to bite the fins between members of their own school. Under ideal conditions, this predisposition does not usually cause major problems and they will not end up causing damage.

To avoid the drawbacks of aggressiveness towards other fish, it is always recommended to maintain a school of a minimum of 5 members or more. In this way we can counteract their aggressiveness making them feel safer. A school with a greater number of members is recommended as long as the volume of the aquarium allows it. The minimum to provide it with adequate conditions is in an urn with a length of 60 cm. In addition, providing a habitat with plants, some floating that dim the intensity of light, and places to hide, will end up providing the protection it requires and thus avoid aggressive behavior towards other fish.

If we have doubts to make it compatible with other fish, it would be best to decide on quieter species of tetras.

In case of overcoming the disadvantage of the character of the Serpae Tetra, we can enjoy a species that shows off a beautiful color exhibited by very lively fish, which walk in a school, and that will stand out even among the plants and the dark areas of the aquarium.

Scientific classification

The scientific denomination is Hyphessobrycon eques (Steindachner, 1882). We are dealing with a typical characin (family Characidae) in whose genus Hyphessobrycon more than 100 species of tetra fish are cataloged that come from the so-called neotropics or tropical ecozone. The vast majority of these fish are found in the rivers of South America.

In the genus Hyphessobrycon, a consensus has not always been reached on the classification of the different species that compose it. It is accepted that some characteristics that define it are the typical adipose fin of the characins, two series of teeth in the premaxilla with the outermost teeth distributed in a simple series, and an incomplete lateral line.

The species Hyphessobrycon eques has also been known by various scientific names such as Tetragonopterus callistus, Hemigrammus serpae, or Hemigrammus melanopterus.

The variety of common names is due – normally – to its coloration and it does not fall short: serpae tetra, fire blood tetra, jewel tetra, red tetra


The species is native to South America and is found in the basins of the Guaporé and Paraguay rivers and in tributaries of the Amazon, covering the territories of three countries: Brazil, Bolivia and Paraguay. It lives in calm areas and stagnant waters, always surrounded by a high density of plants.

The climate is tropical with a water temperature between 22º C and 26º C, normally with a preference for slightly acidic waters between 5.0 and 7.8 pH, and hardness between 10 and 25 dH.

Morphology and Color

The maximum size is 4 cm in nature. In captivity they could reach about 5 cm.

This is a tetra with the typical morphology of these, but considered one of the most beautiful for the vividness of its colors. It is popularly called in many different ways, almost always referring to some characteristic of its color that ranges from an intense color to brown. The caudal fin is completely red; anal red with a possible black outer edge ending in white towards the middle of the body; a long dorsal fin changes the previous patterns and stands out for its mainly black color. The eyes are black.

One of the typical characteristics is the black mark on the cover of the gills that almost all specimens of the species have. This hallmark in black color is variable and can be large, small or even not exist in some fish; the most typical thing is that with age this black area becomes smaller.

Their colors are appreciated when we provide them with an aquarium with characteristics close to those they have in their natural habitat, evidencing greater joy in aquariums with good plant growth in which their colors shine fully, thanks to a lively movement, they will walk in schools throughout the tank.

Sexual dimorphism

Sex differences are not at all obvious. You have to look at the color and the belly. Males sport a slightly greater intensity of color than females. When the breeding season approaches, the females usually show a noticeably bulkier belly, giving them a more rounded shape.


Without difficulty. In nature it is an omnivore that eats insects, crustaceans and plants. Likes live food, flakes or frozen food. It will accept any commercial preparation that suits its size. A rich and varied diet helps to highlight its color.

When it comes to feeding it, it shows its greatest display of aggressiveness with rapid movements and being able to peck at each other.

Behavior and Compatibility

In general, we can say that like all tetras it is an easy maintenance fish, affordable for all levels. But it is accompanied by a negative fame acquired by nibbling the fins of other fish. Without a doubt, we are facing one of the tetras that shows a greater bellicosity.

Its aggressive behavior must be alleviated by maintaining a school with a number of specimens adequate for the size of the aquarium. For an urn with a minimum estimated length of 60 cm, half a dozen serpae tetras should be considered, recommending expanding the group if we have a larger volume in our aquariums.

They are gregarious fish to which the group will give them security by mitigating aggressive behavior. For this, it is also recommended proportional hiding places in rocks or caves, and fundamentally an aquarium overflowing with plants. They respond well in aquariums with spaces to hide between rocks and plants, which can be floating or tall plants that help them feel confident with their habit of swimming in the middle or upper zone of the aquarium; in the wild enjoys being close to the surface surrounded by plant stems. The species prefers low light intensity; floating plants will help us dim the light in certain areas of the aquarium.

By maintaining a good number of individuals in the shoal and providing it with conditions similar to those of its natural habitat, we can prevent it from revealing signs of attack. If you have few Serpae Tetra or the aquarium does not provide the necessary security, you should avoid mixing them with smaller tetras and any type of species that has delicate tails: bettas, gouramis, guppies, etc.

Nor should we forget that it is still a tetra, so it is recommended not to combine it with aggressive or very large species that would endanger the tranquility of the school.  Amoxicillin for fish  ampicillin for fish

Life expectancy

In captivity and with the right conditions for its maintenance, it can live up to 5 years and even exceed them.


One of the attractions for the aquarium hobbyist is that the Serpae Tetra is one of the easiest tetra species to breed in captivity. Small aquariums of 3.20–4.80 gal with black substrate and plants such as cabombas, myriophyllum or java moss should be used. Water with a sensitive acidity (between 6 and 7 ph), and hardness between (4 and 8 dH). When the eggs are fertilized, the parents must be removed to prevent them from being eaten. Hatching occurs in 24-28 hours.