Congo Tetra (Phenacogrammus Interruptus)

Congo Tetra (Phenacogrammus Interruptus)

The Congo Tetra is a freshwater fish native to the Congo River Basin in Africa.

These peaceful fish are popular among aquarium enthusiasts for their beautiful fins and stunning coloration.

While Congo Tetras are not difficult to care for, there are a few things potential owners should know before adding them to their tank.

This article will cover everything you need to know about Congo Tetras, from their natural habitat to their ideal tank mates.

Whether you’re an experienced aquarist or a beginner looking for a new addition to your fish tank, Congos will make a splash!


Originthe River Congo and Central African rivers
AggressionThey are generally peaceful. 
Minimum Tank Size20 gallons
Length2.5 to 3. 5 inches
Ease of Carerelatively easy
pH6.0 – 7.5
Temperature72-82°F (22-28°C)
BreedingEgg Scatter
Life Span3-5 years, possibly longer

Congo Tetra Origins

The Congo tetra (Phenacogrammus interruptus) is a freshwater fish found only in the Congo River basin in Central Africa.

It belongs to the characin family, including African tetras (Alestiidae).

This species is a popular aquarium fish that has been introduced to numerous nations across the world, including the United States, Germany, and the Netherlands

CongoTetra Lifespan & Life Cycle


The average lifespan of a Congo tetra in the wild is about three years, but they can live up to six years in captivity.

Life Cycle:

Congo tetras have a life cycle that is relatively simple compared to other fish species.

They are egg layers, meaning that the eggs are fertilized outside of the female’s body and then laid in water.

The eggs hatch into larvae, which are tiny and unable to fend for themselves. 

The larvae live in the water and are fed by their parents until they grow large enough to survive independently.

Congo tetras grow fast; it takes two weeks for Congo Tetra fry to reach 1 inch and another three months to grow to 2 inches.

 The colors of the Congo Tetras will become more apparent at the 3-month mark, and at six months, they’ll be 3 inches long on average.

Once the larvae reach a specific size, they undergo a process called metamorphosis, during which they change from their larval form into their adult form.

After metamorphosis, they are ready to start life as adults.

Adult Congo tetras typically live in groups called shoals.

These groups can protect from predators and help the fish find food.

Adult Congo tetras spawn by releasing their eggs and sperm into the water, where fertilization occurs.

The eggs hatch into larvae, undergo metamorphosis, and become juvenile Congo tetras.

The juveniles grow into adults, and the cycle begins anew.

What Are the Features of  Congo Tetra?


The Congo Tetras’ huge fins are one of the most prominent features. 

They also have an iridescent sheen! This pearlescent finish gives a beautiful rainbow appearance. 

Depending on how the light reflects off their bodies, you may observe hues ranging from blue to gold to purple to turquoise. 

2. Color

The Congo Tetras have broad, flattened bodies and enormous scales.

From back to front, they are brightly illuminated with rainbow luminescence.

They’re generally blue on top, red and gold in the middle, and blue on the belly. 

Males have long, flowing, purple fins with white edging; the mail’s tail fin is long and cruising along the vertical medial line.

Weight & Length

Although determining the precise length and weight of the fish is difficult due to various circumstances; this is a general guide for the size of the Congo Tetra.

This fish is a tiny fish that can reach up to 3.5 inches long and weigh around 1.5 grams.

Is Congo Tetra Hardy?

Yes, Congo tetras are pretty hardy and can adapt to a wide range of water conditions.

They are not particularly fussy eaters, so they make an excellent choice for beginner aquarists.

However, it is crucial to provide them with plenty of hiding places and a dark substrate to help them feel comfortable and reduce stress levels.

Congo tetras are also quite shy, so a large tank is recommended to give them plenty of space to swim and hide.

How to Care for Congo Tetra?

1. Tank Size

When caring for Congo tetras, you should remember that their tank size is essential.

These fish can grow up to 3 inches long, and they love to be kept in schools of six or more.

They need a larger tank with more swimming areas so that they do not get stressed out.

So, a tank of at least 30 gallons is recommended.

2. PH Level

The pH level is another crucial factor to consider when stocking a tank with Congo tetras.

These fish are comfortable in soft acidic water, so you’ll need to adjust the pH level of your tank accordingly.

From our experience, we recommend a  pH level of 6.0 to 7.5.

You can use a CO2 system, water conditioning agent, or natural product like peat or alder cones to achieve the desired pH level.

3. Lighting

As with most fish, Congo tetras prefer dark environments.

They are therefore most comfortable in tanks that are dimly lit.

However, they can adjust to well-lit tanks if given time to acclimate.

A good rule of thumb is to aim for a lighting level equivalent to a shaded park on a sunny day.

If you have a tank with very bright light, you can try to mitigate this by adding some floating plants or placing the tank in a darker corner of the room.

It’s important to avoid using bright white light bulbs in your Congo tetra tank.

Instead, opt for bulbs that emit softer, more subdued hues.

This will help your fish feel more comfortable and less stressed in their environment.

4. Temperature

Congo Tetras are tropical fish, so they need warm water to thrive.

The optimum water temperature for Congo Tetras is 73 – 82 degrees Fahrenheit (23 – 28 degrees Celsius).

If the room temperature is too low, you will need to provide a heater to keep the water warm enough for your fish.

5. Filters

Although congo tetras make beautiful additions to any tropical fish tank, they are known to be messy eaters.

Because of this, it is essential to have a good filter in your tank to keep the water clean.

Filters help remove debris and waste from the water, keeping your fish healthy and your tank looking its best.

6. Tank Decoration

Tank decoration is a great way to improve the appearance of your tank and can also provide some interesting hiding places for your fish.

One popular type of tank decoration is rocks.

Rocks come in many shapes and sizes and can be found at most pet stores.

Be sure to choose rocks that are safe for your fish and not harm them if they decide to nibble on them.

Another popular type of tank decoration is plants.

There are many different types of plants that can be used in aquariums.

However, some plants also require special care, so read the instructions carefully before adding them to your tank.

Some examples of safe plants to use in a tank with Congo tetras are:

Anubias barteri, Java fern, and Cryptocoryne.

Congo Tetra Diet

Congo tetras are not picky about what they eat.

They are omnivores which means they will eat everything from pellets to flakes, frozen food, and live crickets.

To guarantee that they receive all of the nutrients they require to remain healthy and strong, give them a varied diet full of worms, insects, crustaceans, brine shrimp, and fresh flake foods.

To guarantee that they consume everything you give them, feed them with just what they can finish in under 3 minutes.

Also, to improve the likelihood of the fish eating the meals, feed them several times a day.

Congo Tetra Compatibility

Congo tetras are peaceful fish that make an excellent addition to any aquarium. 

They get along well with other fish species, and they aren’t overly aggressive.

So, they’re a perfect choice for people seeking a compatible fish.

Congo Tetra can be kept with the following fish:

  • Corydoras
  • CatfishGouramis
  • Rainbowfish
  • Cardinal Tetras
  • Neon Tetras
  • Guppies
  • Mollies 
  • Dwarf Cichlids
  • Harlequin Rasboras
  •  Glowlight Tetra 
  • Barbs

Congo Tetra Predators:

  • Tiger Barbs
  • Some large fish of tetra
  • Some cichlids like the Parrot Cichlids
  • Freshwater sharks

Is Congo Tetra Reef Safe?

Yes, They are safe for both freshwater and saltwater aquariums.

They are robust fish that can tolerate a wide range of water conditions.

To avoid tension, though, it’s essential to acclimate them gradually to any new setting.

Congo Tetra Gender Difference

There are some key differences between male and female Congo tetras.

Males tend to be more brightly colored, while females are usually dull in appearance.

Males also have a long fin on their tail, known as the caudal fin.

This is used to attract mates and can be twice as long as the female’s fin.

Interestingly, while the male Congo tetra is typically more colorful, it is also the less aggressive of the two sexes.

Females are often seen chasing and harassing males, while males will usually only fight when necessary.

This makes the male a better choice for a beginner’s tank, as they are less likely to experience problems with aggression.

Congo Tetra Breeding

Breeding the Congo Tetra can be complicated, but it is doable in a home aquarium.

The breeding process begins with selecting a compatible pair, and it’s important to choose two healthy fish and have a good temperament.

Once you’ve chosen your breeding pair, it’s time to get them ready for breeding.

This involves conditioning the fish with plenty of live food and a breeding tank that is large enough for the fish to swim around in.

The actual breeding process will involve the male chasing the female around and eventually spawning.

The parents will deposit eggs on the plants in the tank, and it is up to the parents to care for them until they hatch.

After the eggs have hatched, it is essential to remove the parents from the tank so that they do not eat their offspring.

The fry will need to be fed live food until they are large enough to eat pellets or flakes.

Remember to be patient and take things slowly, and you’ll be rewarded with a beautiful new addition to your fish tank.

Possible Diseases and Prevention: Congo 

tetra can be susceptible to a few diseases, including

Ich, Fin Rot, and Velvet.

To help prevent your fish from getting sick, keeping the tank clean and providing a healthy diet are essential.

Also, make sure to quarantine any new fish before adding them to your tank.

If you notice any of the following signs, take your fish to the vet immediately:

  • White spots on the skin
  • Red or bloody fins
  • lethargy
  • Loss of appetite

By being proactive and taking good care of your fish, you can help prevent diseases before they have a chance to take hold.

Last Words

The Congo tetra (Alestopetersius trewavasae) is one of the world’s most beautiful and hardy fish.

These fish are popular in aquarium keeping because they are bright and easy to care for.

If you want to keep one in your tank, acquire a healthy individual and feed and care for it until it’s ready to breed.

We hope you have enjoyed this article as much as we did.

If you still have any questions, please share them with us in the comment section below.