Serpae tetra is the sort of fish that you find commonly in many domestic aquariums. Their vivid red hues and attractive look make them appropriate as pets.

These fish look pretty fascinating with different shades of red and display a shimmering appearance when exposed to light.

They move in short spurts of speed, and this unique twitching pattern of swimming fascinates fish keepers all over the World.

Longfin serpae tetra is another variant of serpae with similar morphological features but holds significantly larger flowing fins.

Keep reading to discover more about their breeding, eating habits, and how to make your tank suitable for Serpae tetra.

Review of the Species

Quick Species Facts
Scientific Name Hyphessobrycon eques
Other Common Names Jewel Tetra, Red Minor Tetra, Callistus Tetra
Family Characidae
Origin Brazil, Argentina, and Paraguay
Average Lifespan 5 years
Max. Length 1.6 inches
Type Freshwater fish

Origin and Habitat

Discovered in the tropical regions of South America, the serpae tetra primarily comes from the Amazon River catchment, along with the Paraguay and Guapore river basins.

The favorable conditions in Northern Argentina, Brazil, Paraguay, Bolivia, and Peru witness the existence of these fish. They have later been introduced in French Guiana.

It is a typical freshwater fish and prefers living in slow-movement water, which is warm and neutral to slightly acidic.

But they are also observed thriving comfortably in stagnant backwaters, ponds, lakes, or streams with abundant vegetation, where they collectively hide close to the stems.

Serpae Tetra fish size, lifespan and other facts

Maximum Life Expectancy

According to the expert survey, these fish can complete seven years when raised in captivity if the conditions are optimal for them.

But there is evidence shown by fish enthusiasts claiming the serpae tetra can survive close to ten years in their fish tanks.

On an average, they can roughly live 3 – 5 years in fish tanks.

Size and Appearance

Serpae tetra is a cute and small fish having a maximum size of 4 cm. However, there are exceptions to be witnessed, reaching about 5 – 6 cm when they met favorable conditions.

They present a genuine fish body style, which is thin, and flat in structure, like a parallelogram decorated with anal and dorsal fins and ends in a fanning tail. These features enable them to move at high speed for short distances.

The color varies from bright orange to fire-red, mainly at the corners, and lightens towards the center. It gets highlighted due to the glistening scales.

The rectangular-shaped anal fin has a black streak along with a white-colored border and a red base. The dorsal fin is an almost black square with translucent edges. The tail effortlessly merges with the body color.

Note: The vibrant color shades keep changing as they mature into adults; the color starts diminishing or becoming pale as they reach their maximum age.

A few prominent features of Serpae Tetra include a black spot in the shape of a “comma” adjacent to the gills, a black dorsal fin, and a white outline on all their fins. Some individuals may not have that outline.

How to Tell if It’s a Male or a Female?

The red tetras show negligible distinguishing features in their physical character is tics to identify male and female species. So, it is difficult to differentiate them unless they are observed very closely.

Here are a few noticeable differences between them.

  • The male Serpae Tetra matures at 3 cm in length while the females mature at 2.1 cm.
  • The males display more dynamic color patterns than the females, who usually present light shade.
  • The males have completely dark black dorsal fins, while the females have a dull shade on the fin.
  • The males have a sleek body, while the females have an overall rounder body even when they do not have any eggs.

Availability and Price

Serpae Tetras are bred globally throughout the year, and it doesn’t cost much to raise them.

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It can easily be found in local aquarium shops and even in online stores worldwide at low prices with different shipping charges.

Tip: You can get them at a cheaper rate if you buy them in bulk.

Their price generally varies between $1 to $4 depending upon the vibrancy of the red color and size.

Brief Guide

Care Facts
Care Level Easy
Breeding Egg layer
Social Temperament Peaceful
Diet Omnivorous

Food and Diet

Serpae Tetras are omnivorous, as they eat all kinds of fish food. They mainly feed upon insect larvae and sometimes on aquatic plants in the wild.

In captivity, they can be given the following listed food items.

  • Fresh vegetables – carrots, cucumber and lettuce leaves
  • Bloodworms (frozen or fresh) (occasionally)
  • Shrimps (fresh, brined, or frozen)
  • Earthworms
  • Low and high-quality flakes
  • Fish pellets

For an ideal diet, veggies and fresh bloodworms are recommended. Other than that, high-quality flakes or pellets are good enough if you are on a tight budget.

Pro Tip: Their diet should consist of little food consumed within 2-3 mins. They should be fed only twice or thrice a day to avoid overfeeding and, in turn, preventing excessive murkiness of the water.

But one should bear in mind that sustaining a high nitrogen diet is not particularly good for them and may lead to various disorders.

General Behavior

Serpae Tetras are generally peaceful and social. They are not lone fish and tend to stay happier in schools.

But they often show combative tendencies or start fin nipping activities towards other species. The best way to curb this attitude is to put them in groups.

Author Note: The male fish sometimes behave aggressively towards each other, but this never turns into actual fights or hurting each other.

These fish swim in the mid-level area of the tank and move towards the surface during feeding or when feeling unwell.

Breeding in Artificial Setup

Serpae tetras are among the easy-going aquatics in terms of reproduction. It is a prominent reason behind developing multiple varieties of these species in captivity, having long fins.

These are oviparous fish that spread the eggs wildly over the vegetation and do not show any parental care towards them.

Since they rarely show territorial mood or aggression while breeding, you can induce a pair of these fish in the spawning tank and harvest a large amount of fry.

Fact: According to research conducted by a journal of the Centre of Tropical and Subtropical Aquaculture (CTSA), their preferred time for spawning is around late autumn.


To begin with the mating process, you must have a small separate fish tank of about five gallons. A small filter can help create swift water movements.

Keep the tank in a low-light area, and put the spawning mops or floating plants such as java moss, dimming the visibility.

Fact: The serpae tetra matures at 8 – 10 months of age and can reproduce young ones.

You can induce the pairs in the evening after feeding them with live food properly. A suitable male would have bright colors while females look fatty.


The chasing and stimulation of the female abdomen by the male generally occurs in quick succession, followed by the spawning of eggs.

The spawning behavior is typically seen at temperatures between 23-27°C, with water being slightly acidic. The eggs get scattered over the mops where fertilization occurs.

It is observed that the body color changes to dark green in both genders during spawning, followed by the release of spermatozoa by the male to fertilize the eggs.

Fact: These fish prefer morning hours for spawning, and the females can lay up to 300 eggs after each spawn.

Hatching of eggs

After 16 – 24 hours of incubation, the eggs will hatch into sac-fry (babies). For about five days, you can feed the fry or larva with infusoria-type foods. Later they will be able to eat regular food such as worms or brine shrimp.

Quick Tip: Move the hatchlings to a new tank as soon as possible to prevent them from becoming food for the fish.

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Distinguishing the gender of the hatchlings is difficult during the early stages until they develop their prominent male and female traits seen after some maturation.


Serpae tetra is pretty hardy and possesses good tolerance to changes. But experiencing high-stress conditions for a long time, considering the dirty tank water, can lead to various diseases and disorders.

The tank may get infected for multiple reasons, such as infected plants, décor items, and even other diseased species that can trouble the environment.

No matter what kind of contagious disease is affecting the jewel tetra, it is always advised to quarantine them and avoid further spread.

A few commonly occurring diseases are as follows:

Fin and Tail Rot

Caused by various species of aquatic gram-negative bacteria, rotting begins from the tip of the fins. It gradually moves towards the fin base, making them unable to swim or move in the water.

Treatment – Moving the fish to a quarantine tank and using antibiotics.

Mouth Fungus/Columnaris

Mouth Fungus/Columnaris in Fish

Bacteria:- This disease is caused by Flavobacterium columnare. The infection occurs in the gills, and cloudy patches on the gills are typically seen. Breathing becomes a struggle for the fish.

Treatment- Specific antibiotics like Terramycin can be used, and bath salts can be put in to reduce stress during the treatment.


Dropsy in Serpae tetra

It can be caused by kidney failure or bacterial infection. Disruption of fluid regulation inside the fish body results in a swollen over-rounded body. Lethargic movement and low activity gradually lead to a slow death.

Treatment – Transfer the fish to a ‘hospital’ tank and treat the water with Epsom salt to release some fluid stress from the body. Broad-range antibiotics can be used if the disease is caused by a bacterial infection and maintaining an organic and fresh food diet can be helpful.

White Spot Disease (Ich)

A freshwater parasite known as Ichthyophthirius multifiliis is responsible. Tiny white spots (about 1mm in diameter) appear all over the fish’s body. It is a deadly disease if it is not detected at its early stages.

Treatment – Moving the fish to a quarantine tank and adding zinc-free malachite to prevent the further spread of the parasite.

Serpae Tetra: Care Guide, Breeding, Tank Size

Tank Care

Quick Tank Facts
Water Temperature 72 – 80°F
Minimum Size 10 –20 gallons
Water Hardness  10 – 20 dGH
pH Level 6 – 7.5
Minimum population 5 – 6
Nitrate Content <40mg/L
Brackish No
Water Movement Low to moderate

Ideal Tank Size

To pet a tiny fish like this, you do not require a big tank. But considering their socially active nature, you must arrange a minimum of 75-liter aquarium to house a maximum of 5 – 6 fish.

A smaller tank of about 40 liters may do good for some time when Serpae tetra is immature, but it should be replaced in a year with a bigger fish tank of appropriate size as per the number of aquatics.

If they don’t get enough swimming space, it may lead to increased stress levels and hamper the lifespan of the fish.

Tank Setup


A wide range of natural freshwater foliage is usually preferred as they provide natural oxygen and hiding spots for serpae tetras. These hiding spots work as a stress buster for them.

Floating ferns such as Salvinia can be used to mimic their natural habitat. Other floating plants, such as water lettuce, also known as Pistia, can act as a shelter for the hatchlings and help repel the growth of algae in the tank.

Bryophytes or aquatic moss such as hornworts and java moss quickly grow in household aquariums which becomes a food source and shelter for the fish.

Amazon sword, a popular choice for aquarists, provides a contrasting background for the red fish.


Dim or subdued lighting is ideally preferred to imitate the dark environment of serpae tetras’ natural habitat. Along with that, low lighting also accentuates their bright colors in the background and helps incubate their eggs.


Serpae tetras can be kept on any substrate, whether sand, gravel, or even bare bottom. But generally, dark-colored and sandy substrates are used to complement its colors and give it a natural feeling.

Driftwood could also be used, which provides good hiding spots and adds to the natural aesthetic beauty of the tank.

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Oxygen and Filtration

The addition of aquatic foliage in the tank can provide adequate oxygen for the serpae tetra without adding any extra equipment; however, a simple bubbling air pump would suffice for the oxygen requirement.

Expert Advice: Monthly renewal of 20-30% of the tank water should be carried out to prevent excessive murkiness of the water.

A standard air-driven sponge filter is good enough for filtration purposes as it has a gentler flow.


Although there are no specifics to decorating a tank, everyday items like marble chips, pebbles, stones, driftwood, green aquatic plants, and mosses bring out their vibrant colors.

Author Note: Use dark-colored decorations to favor the contrasting colors of the fish.

Plastic decorations can be used, but it is not recommended as they are not biodegradable, and the sharp edges can harm the fish.

Water Parameters

The natural habitat of serpae tetra is freshwater river basins with dense vegetation where the oxygen concentration is relatively high. Similar situations can be derived by following the below-given guidelines and parameters.

  • Air pumps and aquatic plants can help create freshness with the a slow momentum of water flow.
  • Water temperature should be kept between 23-27°C
  • They prefer pH from 6 up to 6.8
  • The water hardness should be kept between 10-25 dGH. Being freshwater fish, they prefer soft water but can tolerate a high level of hardness for a short period.
  • The nitrate concentration of the tank should be maintained close to 0 but should not exceed 40mg/L. High nitrogen will lower oxygen levels and negatively affect the growth of juveniles.
  • Water should be renewed and replenished by clean water bi-weekly (20-30% volume of the tank). It is advised to use a few drops of an anti-chlorine agent after each change and renewal. Avoid filling directly with tap water as it may be infected and contain harmful chemicals such as Chlorine and Chloramine.

Tank Mates

The serpae tetra is considered a friendly companion to other species and perfect for a community tank, provided the mates are similar or smaller in size.

They mostly stay in groups that keep them high-spirited and indulge with other fish in the tank.

But you should not put in slow-moving fish with long-flowing fins such as Angelfish or Bettas with them as they tend to bite and nibble on their fins.

Generally, other Tetra species, loaches, plecos, danios, cichlids, and some catfish are compatible. They have been shown to exhibit peaceful behavior when kept with serpae tetras.

A few of them are listed as follows:

Expert Advice: Serpae tetras are more compatible with fast and agile companions that match their speed and level of activeness. So, they should be put in the tank together to maintain a peaceful, less stressful environment for everyone.

When keeping different fish species together, always keep an eye out for any aggressive behavior caused by overcrowding. A tank must have enough space for all the fish to swim freely without feeling stressed.

Frequently Asked Questions

Are serpae tetras aggressive in nature?

They sometimes show slight aggression when they feel stressed or when put in smaller groups, but otherwise, they are peaceful fish. Keeping them away from long-finned and slow-moving fish are suggested as they may feel irritated by them and bite on their fins.

Can serpae tetra be put in schools with other tetras?

Yes, they can be put in with other tetras as they have similar personalities and sizes. All tetras are generally agile and show non-aggressive behavior to wards each other.

How many Serpae Tetras can be put in a 5-gallon tank?

They require a lot of space to move around. So if it is a compulsion, you should only induce a pair, as they make good company for each other. More fish will cramp the space and irritate them.

How long can serpae tetras go without eating?

Fish like tetras generally don’t last more than a week or two at maximum without food. They are small and don’t have sufficient fat storage for their energetic movements.

Can they live with shrimps?

Keeping these two aquatics together wouldn’t be a good choice, as the serpae will attempt to predate the shrimps. However, if you are planning to keep them together, then ensure many hiding places in vegetation and substrate to enable the shrimps to stay alive for a longer time.

Final Thoughts: Should We Get Them Home?

Serpae tetras are preferred as aquarium pets by beginner aquarists, as they are incredibly charming, and sustain comfortably in a mixed aquarium.

They are an excellent ornamental aquatic and make your aquarium stand out as a soothing visionary sight. They are resilient and can survive changes in their environment to quite an extent.

You can have them as an affordable and hassle-free tank pet that puts up the least demands regarding food, care, or breeding.

About the Author

Victoria Lamb

Victoria is a freshwater aquatics specialist, fish keeper, and amphibian enthusiast. She has had more than 6 years of experience caring for aquariums and keeping several fish species, and her home boasts of 3 aquariums and a garden pond. Her goal is to educate fish owners on raising healthy and happy aquatic pets. Career Highlights:…

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