Congo Tetra 101: Care, Tank Mates, Size & More

The Congo Tetra is a beautiful freshwater fish that is a piece of cake to care for. It doesn’t matter if you’re a beginner or an expert looking for something low-maintenance, this species is a great choice.

But even though these fish aren’t difficult to keep it’s still important to understand their requirements. Too many aquarists underestimate “easy” fish and end up wondering why things went wrong.

And that’s why we put together this guide. It will show you everything you need to know about Congo Tetra care!

Let’s get started.

Species Summary

Revered for their vibrant colors and eye-catching shimmer, the Congo Tetra (Phenacogrammus interruptus) has become a widely popular freshwater fish species in the aquarium community. They were first discovered in 1949. However, due to breeding difficulties, it wasn’t until the 1970s that these fish became a staple in tanks across the world.

As their name would suggest, these fish are endemic to the Congo River basin. They typically call small streams, ponds, and marshes in the area home.

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They’re a schooling fish and typically stick to large groups in the wild. In captivity, this schooling nature creates stunning swaths of color that will be the center of attention in your tank.


The typical Congo Tetra lifespan is only between 3 and 5 years while in captivity. Some fish-keeping enthusiasts have seen their fish live a bit longer than that, but it’s rare.

As always, the best way to help these fish live as long as possible is to provide them with a happy and healthy environment. Congo Tetras are prone to stress, so staying on top of their diet and water conditions is essential.


It’s not hard to see why these fish are so sought-after. They have a very unique appearance that helps them stand out in any environment.

A side view of the Phenacogrammus interruptus

Their bodies are relatively long and flat. The midsection of the fish is quite tall, giving them a somewhat compressed look. Typically, males are slightly larger than females. But the females are plumper, especially when she is ready for breeding.

The body is complemented by long, semi-transparent fins. Male specimens are quite stunning. They have longer dorsal fins than their female counterparts. As a whole, all of the fins on a male fish have a wispy appearance that flows beautifully in the water.

The fins on male fish have a somewhat purplish hue. The purple color is accented nicely by staunch white edging.

While their fins are a joy to watch as your fish swim around, it’s their color that really stands out. Congo Tetras have considerably large fins for their size. Not only that, but they take on an iridescent shimmer!

This iridescent finish provides a distinct rainbow appearance. Depending on how the light reflects off their bodies, you might see shades of blue, gold, violet, and turquoise. Usually, Congo Tetras have a noticeable stripe that runs from the head to the tail. It’s located on the midsection of the fish and is surrounded by the color-changing luminescence.

Congo Tetra Size

The average Congo Tetra size is between 3 and 3.5 inches long in captivity. Congo Tetras are relatively small, but they’re a bit larger than most types of tetras.

In the wild, Congo Tetras get a bit longer. They can usually be found reaching lengths of 4 and a half inches. Like a lot of captive fish, they will stay on the smaller side when raised in tanks.

Author Note: Owners who have been able to push this 3 and a half inch max size have kept them in an aquarium far larger than the minimum recommended tank size (and provided great care of course).


Congo Tetra care is relatively easy because it doesn’t take much to keep these fish happy. However, you still need to be knowledgeable and provide them with the right habitat and water conditions.

The good thing is that this species is pretty hardy, meaning you have some flexibility when it comes to water parameters. But don’t let that trick you into thinking they can make do with subpar care.

Their tanks need to be maintained properly to keep them in good health. Not only will proper conditions help avoid stress, but they’ll also keep that lustrous color looking great!

Tank Size

Our recommended tank size for Congo Tetras is 30 gallons. You don’t need a huge tank to keep these fish happy and healthy!

Some aquarists have seen success in 20-gallon tanks, but we like to go a little bit larger. As we mentioned earlier, these are schooling fish. They need to be kept with several other fish of the same species to stay happy.

For that reason, it’s a good idea to provide a 30-gallon tank or more. A larger tank will allow you to increase the school population, decorate the tank a bit better, and give your fish more room to roam.

Water Parameters

If you want to keep your fish happy and stress-free, you need to imitate their natural environment as much as possible. This doesn’t just apply to decor. Water conditions are one of the most important things you need to replicate.

Congo Tetras hail from the Congo River basin in Africa. Temperatures are warmer there. Typically, the streams and ponds they reside in are on the murkier side as well.

While you don’t need to dirty up the water to keep them healthy (please don’t do this), it is a good idea to mimic the water composition. Murky waters like that are on the acidic side and have fewer minerals.

Luckily, Congo Tetras aren’t super picky. As long as you stay within the following parameters, you should be good.

  • Water temperature: 72°F to 82°F (76°F should be your ideal target)
  • pH levels: 6.0 to 7.5 (stick to the lower end of this range)
  • Water hardness: 3 to 18 dGH

Author Note: Stability is very important for these fish, even if they can survive in a wide range of water parameters. That means you should be testing your water consistently and doing whatever it takes to make sure your aquarium doesn’t see any significant shifts in these levels.

What To Include In Their Tank

Once you have the water conditions just right, you can start focusing on decor! In the wild, those murky waters they call home are filled with tons of hiding spaces under the surface.

You can fill the bottom with a dark and sandy substrate. This helps to replicate the muddy bottoms of the river basin.

For the most part, Congo Tetras will stay in the middle and top areas of the tank. They won’t spend a ton of time at the bottom of the tank, but it’s still a good idea to give them something familiar.

Next, incorporate some floating plants, such as Java Fern. Congo Tetras feel comfortable when they have plenty of plants in their habitat. Not only does it serve as a place to hide when threatened, but it also provides a bit of protection from the light.

It’s a good idea to arrange your plants in clumps. While it might be tempting to have many areas of vegetation, but you don’t want to overfill your aquarium and make it difficult for the fish to swim. Leave ample room in the center of the tank for the school to group up.

A Congo Tetra swimming in a planted tank

You can also add some artificial caves, rocks, or driftwood into the mix. These provide even more hiding spots for your fish to use.

Make sure that you equip your tank with an adequate filter. A standard canister or carbon filter should be able to keep waste levels low. It’ll work in tandem will the plants to keep nitrates low as well.

Diseases To Watch Out For

Congo Tetras are at risk of experiencing many common fish diseases. However, they are not susceptible to any species-specific problems.

The most common ailment you may have to deal with is Ich. This is a byproduct of stress and can be fatal. Luckily, treatment is relatively simple with isolation and over-the-counter products.

You can prevent Ich, as well as other diseases, by remaining vigilant about water conditions and overall tank maintenance. The important thing to remember is that it’s always easier to prevent diseases than treat them.

Food & Diet Recommendations

These fish aren’t picky eaters. In the wild, they will feed on pretty much anything they can find. This includes insect larvae, algae, plants, and more.

Congo Tetras are omnivores, so they do just fine on dried flakes or pellets. A lot of owners use these as the primary base of their diet for convenience and it works just fine.

However, we recommend supplementing their diet with some nutrient-rich treats as well.

Try giving your fish some live food like brine shrimp, daphnia, tubifex, and bloodworms. Many aquarists also give their fish small pieces of fresh vegetables for a boost of vitamins.

Author Note: We find that mixing up their diet with some of these protein-based foods can be great for enrichment as well. Happy fish are healthy fish!

Temperament & General Behavior

The Congo Tetra is a very peaceful species. In fact, they can get very skittish if there are other fish in the tank that exhibit signs of aggression or intense activity. When in fear, the fish will spend most of its time hiding.

You can prevent this behavior by keeping the tank filled with peaceful community fish. We’ll go over some good tank mates in the section below.

When other fish of the same species are in the tank, they will experience significantly lower levels of stress and be more active. They’ll frequently group up throughout the day and swim around the tank. Every once in a while, they’ll go their separate ways to explore (before returning to their buddies).

In general, these fish spend most of their time in the middle and top areas of the tank. Depending on the size of your tank you might see one check out the bottom from time to time, but that’s not very common.

Sometimes, Congo Tetras may nip at the ends of plant leaves. Usually, this is a sign that they are not getting fed enough. Provide your fish with some food and the behavior should stop.

Congo Tetra Tank Mates

There are a number of options when it comes to picking Congo Tetra tank mates. These fish are the perfect addition to peaceful tanks and do very well with similarly sized fish that are gentle and passive.

The best tankmates, of course, are other Congo Tetras. We recommend getting a group no smaller than 6.

The more Congo Tetras you have in the tank, the better. Just make sure that your tank is big enough and has plenty of room to swim.

Here are some other species that make good Congo Tetra tank mates:


Interested in breeding Congo Tetras? You’ll be happy to know that it’s a fairly simple process. These fish are egg layers. Females can produce up to 500 eggs at once, leaving you with a huge school of fry to take care of.

To initiate the breeding process, set up a 20-gallon tank. Place peat moss at the bottom. You can also add some breeding mops and plants throughout. After adding the water, let the tank cycle for several days so that the moss has time to enrich the water.

Then, put a bonded male and female into the tank. Raise the temperature to about 77 degrees Fahrenheit and turn off all the lights. When you turn the lights back on the next day, your fish will likely start spawning.

The male will perform a bit of a dance for the female. She’ll then go into the moss at the bottom of the tank. The male then follows to start breeding.

When the female lays her eggs, they will fall into the moss. This is a good thing. It offers protection. Congo Tetras are known to eat the eggs.

Once the fish are done breeding, remove the adults from the tank. After about a week, the tiny fish fry will emerge. You can feed them infusoria for a few days. Then, switch to baby brine shrimp. By the two-week mark, the fish will be large enough to eat powered fish food.            

Wrapping It Up

Now that you have a strong understanding of what it takes to provide good Congo Tetra care, it’s time to decide if this species is right for you.

This species is incredibly low-maintenance and fun to observe in your tank. Trust us, you’ll spend many hours watching these little creatures swim around!

If you have any questions about this species or suggestions on how we can improve the guide, let us know. We’re always looking for ways to make our site better!

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