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Congo Tetra Care Guide: Everything You Need To Know

Congo Tetra Care Guide: Everything You Need To Know

The Congo Tetra is a stunning fish that’s easy to care for if you know everything about them before getting one. Many people love them for their unique, shimmery scales and friendly personalities. 

Everything you need to know about Congo Tetras includes their temperament, water parameters, and common health issues. These peaceful fish prefer acidic, soft water with low light. Replicating their natural environment as closely as possible in your tank helps prevent stress and illness.

If you’re considering getting some, you’ll want to ensure you can provide your Congo Tetras with a suitable environment. These fish can stress easily, so you’ll want to keep reading to learn more about raising them.

Congo Tetra Overview and Natural Habitat

  • Common name: Congo Tetra
  • Scientific name: Phenacogrammus interruptus
  • Care level: Moderate
  • Size: 3 inches (7.62 cm)
  • Lifespan: Four years
  • Temperament: Peaceful
  • Diet: Omnivore
  • Group size: At least six
  • Minimum tank size: 30 gallons
  • Tank level: Mid-top dweller
  • Water temperature: 72 to 82°F (22.22 to 27.77°C)
  • Water pH levels: 6.0 to 7.5
  • Water hardness: 3 to 18 dGH

Congo Tetras are a widespread freshwater fish known for their vibrant, rainbow-like bodies. They’re peaceful and form schools that attract much attention in any tank. However, Congos are a bit harder to care for than other tetras due to how easily they can become stressed.

These fish come from the Congo River basin and are used to the soft, slightly acidic, dark water there. The water is very slow-moving, and the Congos you have at home will surely appreciate it if you can recreate those conditions exactly.

They were discovered in 1899, but the fish were difficult to breed, so they wouldn’t become popular as pets until the 1970s.

Congo Tetra Appearance and Size

Congo Tetras can get much longer than other tetras. Adults usually reach three inches (7.62 cm) in length, but some can get as long as four inches (10.16 cm). 

Congos are long, torpedo-shaped fish with long semi-transparent fins. Their scales are iridescent and have a beautiful shimmer to them. You might see violet, gold, and blue reflect off of them.

Lastly, these tetras have a single stripe that runs from their head to their tail through the middle of their bodies.

Difference Between Males and Females

There are several differences between male and female Congo Tetras that you’ll want to keep an eye out for. These include:

  • The males are noticeably larger than the females, which isn’t the case with many other tetra species.
  • The males have longer, flowing fins. 
  • A male’s tail fin will have a more extended center part that sticks out.
  • The males are more vibrant, and the females are usually blue or green.
  • Adult females have rounder bodies than males.

If you look for these key differences, you’re sure to quickly determine the sex of your fish. You’ll need to do this if you plan on breeding them later.

Congo Tetra Personality and Behavior

Congo Tetras are very relaxed, peaceful fish. Although, they can be wary of other species, especially if they’re more aggressive than the Congos. Your Congo Tetras will always hide if they’re too stressed, so make changes if you notice this behavior. 

The tetras will form a school during the day and spend their time exploring the tank together. They’re most active during this time and will sleep at night. 

Congo Tetras also won’t eat any natural plants you keep in the tank unless they aren’t getting enough food during the day. So, if you see them nibbling on your plants, increase how often you feed them to keep them healthy.

Overall, Congos are skittish fish. They’ll hide from loud sounds, so you’ll need to keep their tank in a quiet room to keep them from getting overwhelmed. 

Congo Tetra Expected Lifespan

You can expect most Congo Tetras to live about four years in captivity. They can usually live up to five years with excellent care, sometimes even longer. 

That said, these tetras are prone to excessive stress. You’ll need to keep up with cleaning their tank and check that their water parameters are exact often. Stress can shorten their lifespan by quite a bit.

Congo Tetra Care and Tank Set Up

You’ll want to create an environment for your Congo Tetras so that they can thrive. You can tell you’re doing well if your fish are vibrant and active and aren’t hiding at the bottom of the tank.

You should set up their water parameters and decorations right to prevent your Congos from getting stressed. Generally, achieving suitable living conditions for these tetras is easy. They’re also hardy, so you have some wiggle room to get it right.

Tank Size

I’ll start with the tank size. Congo Tetras are larger than most other tetras, so they need a bigger tank. That means you’ll want to choose one that’s at least 30 gallons. 

A 30-gallon gives you enough space to fit a complete school of Congos, plus plenty of hiding spaces and open water for them to swim. 

You can always choose a bigger tank and add more fish later. It’s always better to size up if you’re trying to choose between two tank sizes so your tetras are more comfortable. 

How Many Congo Tetras Are Suitable For a 30-Gallon Tank?

Six to eight Congo Tetras are suitable for a 30-gallon tank. You should keep Congos in groups of six or more to keep them from hiding and becoming stressed. You’ll need a larger tank to prevent overcrowding if you want a larger school.

It’s crucial to find a balance with how many Congo Tetras you have in your tank. They become very skittish if their school is too small. However, since they’re larger than many other tetras, you can easily overcrowd them in smaller tanks.

Water Parameters

Next, you’ll want to replicate the Congo Tetra’s natural habitat as closely as possible. These fish come from the Congo River basin with murky, slightly acidic, soft water. The water is slow-moving and contains a lot of plants that block out the light.

You’ll need to keep the water parameters as consistent as possible to keep your fish happy and healthy. So, test the water often to catch any sudden changes.

Water Temperature

The water temperature for Congos needs to be between 72 to 82°F (22.22 to 27.77°C), with 76°F (24.44°C) being optimal. Congo Tetras are highly sensitive to changes in temperature, so you will want to use a heater system to keep it stable. 

Water pH Levels

Congo Tetras like their water to be slightly acidic. You’ll need to keep it between 6.0 to 7.5 pH, but staying on the lower end of that range is best.

You want to keep the water as close to 6.0 pH as possible. If you can do that, your fish will appear brighter and be much more active in the tank. 

Water Hardness

Next, you’ll need to keep the water’s hardness between three and 18 dGH. Congos prefer their water to be soft because they aren’t used to many minerals in their natural habitat.

Adding plants and driftwood to the tank can make the water softer.

Water Current

Congo Tetras do like to have a moderate current in their tank. Adding a filter is usually enough to get the water moving. Although, you’ll want to have some areas with no current for your tetras to rest in. 

Having a slight current replicates the river basin these fish come from, so it helps them feel more at home. However, don’t make the current too strong as it will cause the fish stress.

What To Put in the Tank

Decorating the tank and using the proper equipment will help keep your tetras happy. You’ll want to include a substrate safe for Congos, plus plenty of decorations and live plants.

These skittish fish need many hiding places to feel safe, so you should include caves and plants with lots of leaves. It’s also important to consider what lighting, heating, and filter systems you’ll use.


You should start with the substrate. I recommend choosing dark sand because it looks similar to the bottom of the Congo River basin. Sand is also safe for these tetras since it’s too fine for them to choke on. 

Dark sand also makes the tank look darker overall, which these fish will appreciate. Lastly, sand works well with many live plants, making it convenient.


Next, you can add your decorations. I recommend placing many stones, caves, and pieces of driftwood in the tank. These items give your Congo Tetras a hiding place if something startles them.

Ideal Plants

You want to add plants that help filter light but still can live in the Congo Tetra’s water conditions. I recommend trying water wisteria, water sprite, and java fern. You can also try Anacharis and dwarf water lettuce

Once you have your plants, place them in groups in the tank. You want to create planted areas along the back and sides while leaving the middle open for your Congo Tetras to swim in.

You may notice your tetras nipping the plants from time to time. That’s normal, but if they seem to be aggressively snacking on the leaves, you’ll want to ensure you feed your fish more often. 


Congo Tetras like dim lighting. They very much dislike bright light, so you want to add a lot of decorations and plants to help filter it out. You can use a light fixture, but make sure that you turn it off at night.


Unless you live in a hot place, you’ll need a heater for your fish tank. Tank heaters are great for Congo Tetras because they consistently keep the tank at a set temperature, so you don’t have to worry about sudden temperature drops negatively impacting your fish.

Simply set it to 76°F (24.44°C), and you’re good to go.


A water filter is essential for these tetras since it will help keep the water clean for your fish. Congo Tetras live in large schools, causing them to have a higher impact on the tank.

Since these are larger tetras, you can choose from most types of filters, and they work out just fine. You will want to ensure you don’t get anything too powerful, as it can create a strong current or cause the fish to become stuck.

Finally, perform partial water changes up to 25% of the tank water every few weeks to maintain cleanliness.

Congo Tetra Tank Mates

Congo Tetras are very peaceful, so they can make wonderful tank mates with various fish. However, you will want to only pair them with other peaceful species since they’re so skittish.

The best tank mates are other tetras. For example, you can add Ember, Glowlight, and Neon Tetras to tanks with Congo Tetras. Cory Catfish, Guppies, and Mollies are other wonderful options.

Tank Mates To Avoid

Large and aggressive species are too much for Congo Tetras. They’ll always hide, become stressed, and lose their bright color patterns. The Congos can also become very sick when under constant stress.

So, you should never place barbs, cichlids, or angelfish with them. 

Congo Tetra Food and Diet

Congo Tetras will eat almost anything, but you still need to ensure they’re getting a healthy diet. You can offer them pellets and flakes as the base of their diet. Just make sure to include some nutrient-rich foods as well.

For instance, you can give them live food from time to time. Bloodworms, brine shrimp, and Daphnia are the best for Congos. Then, you can even give them tiny pieces of vegetables for more nutrition.

You’ll need to feed your Congo Tetras in small amounts several times daily. Most of the time, three to four small meals are enough.

Breeding Congo Tetras

You’ll first need to set up a separate breeding tank lined with peat moss along the bottom. It’s also good to include plenty of plants or breeding mops, which are a bunch of string fish can lay their eggs in.

If you want an excellent breeding mop for your Congo Tetras, I recommend checking out the ALUMVAM Fish Spawning Mop from It’s easy to use, increases breeding success, and is made from safe materials.

Next, give the tank some time to cycle with the peat moss. You can then add the fish, raise the tank’s temperature to 77°F (25°C) and leave the lights off for the entire day. When you turn the lights back on 24 hours later, the fish should begin spawning.

The adults will eat the eggs, so remove them from the tank when finished. 

Congo Tetra Common Health Issues

Congo Tetras don’t have any species-specific issues you’ll need to worry about. If you can keep your tetras happy, you can prevent them from getting a lot of diseases.

Below, I’ve broken down this fish’s most common health issue, including symptoms, treatment, and prevention.


Ich, also called white spot disease, can be a problem with tetras. It’s a parasitic infection that’s very common in tropical freshwater aquariums. It occurs when a parasite invades the mucosal tissue of the fish.

Luckily, it’s easy to prevent a sudden outbreak in your tank.

Ich Symptoms

You’ll notice white spots breaking out on your fish, especially around their fins and fills. The spots almost look like salt.

Your fish will look like it’s struggling to breathe as the ich spreads and might spend more time near the water’s surface where there’s more oxygen. The Congo Tetra might also separate itself from the rest of the school and become lethargic.

Finally, you’ll often see the fish trying to scratch itself on objects in the tank.

Ich Treatment

You’ll want to quarantine any infected fish in a separate tank. Once the fish are inside, you must raise the temperature slowly. Doing it too fast can hurt your Congos.

So, raise the tank’s temperature by one degree each hour until you reach 86˚F (30˚C). After that, you can add ich medicine to the tank. It’s a widespread infection, so you can find treatment anywhere.

Ich Prevention

The easiest way to prevent ich is to quarantine any new Congo Tetras, plants, and other creatures you plan on adding to your main tank for a few weeks. Doing so can stop the introduction of it to your community.

Keeping your Congos from being stressed also goes a long way in prevention.

Are Congo Tetras Right for You?

Congo Tetras are right for any fishkeeper who can pay close attention to their tank conditions. These fish stress easily, so you want to stabilize their water temperature, pH, and hardness. Congo Tetras wouldn’t suit you well if you can’t do that.

So, I’d have to say that Congo Tetras are suitable for most people, but you’ll want to have some experience raising other fish first. You can try Neon Tetras, as they’re excellent for beginners.

Congo Tetra FAQs

How Many Congo Tetras Should I Get?

You should get at least six Congo Tetras so they can form a school. If you have a big fish tank, you can always add more. Keeping less than six in a tank will cause the Congos a lot of stress, which can make them sick.

So, as long as you get enough to form a school, it’ll be fine. When you don’t have enough Congos in the tank, they’ll hide and act even more skittish than usual.

Are Congo Tetras Aggressive?

Congo Tetras aren’t aggressive normally. They’re very peaceful and can even be shy. However, they may nip at other fish with long, flowing tails, which can be misinterpreted as aggression.

These fish are very relaxed and excellent for community tanks. Although, you shouldn’t pair them with aggressive species, as they’ll get bullied.

Do Congo Tetras Eat Plants?

Congo Tetras normally won’t eat plants. They may nip at them if they haven’t been fed in a while, but they’ll ignore them if you keep up with routine feeding. Offering them a mix of pellets and live food is best.

So, you won’t have to worry about your Congo Tetras ruining the plants you have in your tank.

Wrapping Up

In conclusion, Congo Tetras are excellent fish for most people. They’re beautiful and fun to raise, but they can stress easily. However, you shouldn’t have to worry about that if you keep their water in good condition.

I’m Elle, the founder of FishHQ. I created this website to share knowledge, tips, and inspiration for beginner hobbyists to help them create a healthy, happy, and vibrant environment for their fish to thrive. Read more...