Cardinal Tetra Care: An Expert’s Guide For Beginners

Caring for cardinal tetras is a rewarding experience for fishkeepers of all levels. Understanding their specific care requirements ensures their well-being and allows you to appreciate their natural behavior and stunning colors. 

That’s why in this article, we’ll learn everything you need to know to keep your Cardinal Tetras happy in your tank. So, keep reading!

TL;DR

Cardinal tetras are beginner-friendly fish that do best in groups of 5-6. They need a tank that is at least 20 gallons and has a temperature between 73-81°F and a pH between 5.3-7.8. They are omnivorous and can be fed a diet of tropical fish flakes, live food, and algae wafers.

Cardinal tetras are relatively hardy fish, but they do need consistent water conditions to truly thrive. With proper care, cardinal tetras can live for up to 5 years. Good tank mates for cardinal tetras include harlequin rasboras, common corydoras, neon tetras, cherry barbs, and small dwarf gouramis.

Some Additional Things To Remember:

• Provide plenty of hiding places in the tank, such as plants, rocks, and driftwood.
• Change the water in the tank regularly to keep the water quality high.
• Monitor the tank for signs of disease and treat any problems promptly.

Are Cardinal Tetras Easy To Keep?

If you want colorful and easy-to-take-care-of fish, cardinal tetras are a great choice. They will make your aquarium look beautiful and bring you so much joy. Just remember to keep the water conditions right, feed them well, and create a comfortable home for them, and they will be happy and healthy!

Taking care of cardinal tetras is straightforward. Just like any other fish, they simply need to live in a clean tank with the right water conditions to thrive. 

Another advantage of keeping cardinal tetras is their peaceful nature. They generally get along well with other calm and non-aggressive fish. They also like to be in groups, so it’s best to have at least six or more of them together. 

Feeding cardinal tetras is easy too. They eat different types of food, like flakes, pellets, and small live or frozen foods such as brine shrimp or daphnia. Giving them a varied diet keeps them healthy.

(Now you know cardinal tetras are great fish for beginners! Here are 15 more of the easiest fish to take care of! According to 150 fish keepers!)

Here’s what other fish keepers had to say about caring for cardinal tetras!

Name	Cardinal Tetra (Paracheirodon axelrodi)
Cost	$2.99-$4.99+ Per Fish
Origin	China
Care Level	Easy
Lifespan	5 Years
Size	2 Inches
Tank Size	20 Gallons
pH	5.3-7.8
Temperature	73-81°F
KH	2-6
GH	1-2
Diet	Omnivores
Feeding	Fish Flakes, Live Food, Blanched Vegetables
Community Tank	Yes
Tank Level	Mid Level
Plants	Java Moss, Anubias, Amazon Sword, Water Wisteria, Java Fern
Tank Mates	Guppies, Neon Tetras, Panda Corydoras, Mystery Snails, Platies, Zebra Danios, Angelfish, Sparkling Gouramis, German Blue Rams, Otocinclus Catfish
Breeding	Difficult
Breeding Type	Egg Layer

Appearance

Cardinal tetras look absolutely beautiful with their bright red and blue stripes. They have slender bodies and fins that move gracefully, and having these fish can make your aquarium look really beautiful and bring joy to anyone who sees them.

Your Cardinal Tetras’ red stripe runs horizontally from the middle of their body to their tail, while the blue stripe starts at their eye and extends along the top part of their body. The contrast between these colors creates a stunning visual display. 

Their fins are translucent with hints of red and blue, adding to their overall beauty. As the cardinal tetras swim, their fins gracefully move, creating a captivating dance of colors in the water.

Additionally, it’s interesting to note that the intensity of your Cardinal Tetras’ colors can vary depending on their mood and environment. When they’re feeling happy and healthy, their colors become more vibrant. However, if they’re stressed or not in the right conditions, their colors may fade a bit. 

So, providing them with a well-maintained and suitable environment is crucial to showcase their beauty.

Size

Cardinal tetras are pretty small fish, and they usually grow to around 2 inches long. But despite their small size, they can bring huge happiness to all kinds of fish keepers!

Even though they are small, cardinal tetras have beautiful colors that stand out. Also, cardinal tetras can live peacefully with other calm fish in a community tank because of their small size. However, it’s important to choose tank mates that have similar needs and behaviors. This way, they can all live together happily.

Behavior

Cardinal tetras are known to be friendly and peaceful. They like to swim together in groups, where they move in sync with each other. This behavior is called schooling, which is a way for them to stay safe from predators in their natural habitat. In an aquarium, watching them swim together is quite a sight to see!

Another thing Cardinal Tetras like to do is stay in the middle and upper parts of the tank. They enjoy swimming in the open spaces in these areas. So, providing them with room to swim and some tall plants or decorations will make them feel safe and happy.

And when it’s time to eat, cardinal tetras get really excited. They eagerly eat different types of food like flakes, pellets, and even live or frozen treats like brine shrimp or bloodworms. Watching them eat is quite entertaining!

Lifespan

If you’re wondering about a cardinal tetras lifespan, then you’ll be pleased to know these beautiful fish usually live for about 5 years if they are taken care of properly.

Cardinal tetras have a decent lifespan compared to some other fish. If you make sure they have a good home and take care of them well, they can live for quite a while and bring joy to your aquarium.

And to help your Cardinal Tetras live longer, it’s important to keep your tank clean and well kept. This means having a good filter and doing regular water changes. Moreover, giving them the right food and enough space to swim and hide is also important for their long life.

And remember your Cardinal Tetras’ genes and overall health can directly affect how long they live.

Water Parameters

Let’s talk about the water parameters that are important for cardinal tetras. These fish have specific preferences when it comes to pH level, temperature, and water hardness.

Name	Cardinal Tetra
pH	5.3-7.8
Temperature	73-81°F
GH	1-2
KH	2-6
Tank Size	20 Gallons

pH

Firstly, cardinal tetras prefer slightly acidic water. The ideal pH range for them is between 5.3 and 7.8. It’s important to maintain a stable pH level within this range to create a suitable environment for their well-being.

Temperature

Next, let’s talk about temperature. Cardinal tetras thrive in tropical temperatures. The recommended temperature range for them is between 73°F and 81°F. Keeping the water temperature within this range helps them stay comfortable and healthy.

Water Hardness

In terms of water hardness, cardinal tetras prefer soft water with low mineral concentrations. So, the ideal range for them is around 1 to 2 dGH. It’s important to note that although they can adapt to a range of water hardness, it’s always best to aim for levels within this preferred range.

Tank Size

Cardinal tetras need enough space to swim comfortably. So, it’s generally recommended to have a tank that holds at least 20 gallons or more.

Cardinal tetras may be small, but they like to swim around a lot. Having a larger tank gives them the freedom to move and explore. It also helps reduce any stress they might feel from being in a small space.

And with a tank size of 20 gallons or more, you’ll have plenty of room for a small group of cardinal tetras. It also allows you to add other fish that can live together peacefully. Plus, you can decorate the tank with plants and things like driftwood, which makes it more interesting for the tetras.

A bigger tank also helps keep the water in good condition. Having more water helps dilute any changes in the water quality, which is important for keeping the fish healthy.

What Do Cardinal Tetra Like In The Wild?

Cardinal Tetras are originally from the Amazon rainforest in South America and have specific preferences when it comes to their environment. In the wild, cardinal tetras can be found in slow-moving rivers and streams, as well as flooded areas. The water in these places is clear and shaded by the trees.

One thing cardinal tetras like in the wild is lots of plants. They prefer areas with plenty of underwater and floating plants. These plants give them places to hide and feel safe from bigger fish.

Another thing they enjoy is slightly acidic water. The pH level in their natural habitat is usually between 5.3 and 7.8, where they feel most comfortable. Moreover, their wild environment is full of small bugs, insects, and tiny creatures. Cardinal tetras like to hunt and eat these as part of their diet.

How To Setup A Tank For Cardinal Tetras 

Setting up a tank for your cardinal tetras is incredibly easy too! Here’s a step by step guide on what you need to remember!

Choosing the Tank

Start by choosing an appropriate tank size for your cardinal tetras. A minimum tank size of 20 gallons is recommended to provide enough swimming space and accommodate a small school of tetras.

Gather the Essentials

To start, gather all the necessary items for setting up the tank, including the aquarium, heater, filter, substrate, decorations, water conditioner, and water testing kit.

Add the Substrate

Spread the substrate evenly on the bottom of the tank, creating a suitable base for your cardinal tetras. Pick your substrate, whether it’s fine gravel or sand. However, Aquarium soil is also a great option, especially because you’ll be adding plants to your tank.

Add Decorations

Start placing plants like Java ferns or Anubias Nana, as well as driftwood, or rocks, in your tank to provide hiding spots and create a comfortable environment for your tetras.

Install the Heater

Install the heater in the tank according to the manufacturer’s instructions, and set the temperature to the recommended range for cardinal tetras. For a tank that is 20 gallons in size you should opt for a heater that’s at least 100 watts.

Set Up the Filter

Follow the instructions to properly set up the filter in the tank, ensuring it provides the right amount of water circulation and filtration. When picking a filter, you should make sure that it turns over 3-4 times the amount of water in the tank per hour.

Add Lighting

Lighting is crucial for the health and well-being of cardinal tetras in an aquarium, allowing them to move, feed, and thrive. Plants also require lighting to grow and produce oxygen for the fish. 

You can choose between Incandescent, LED, Fluorescent, and Metal Halide Lights, but LED is preferable because it’s the most power efficient and emits less heat.

Add Water and Conditioner

Fill the tank with water, treating it with a water conditioner to remove harmful chemicals and make it safe for your tetras.

Test the Water

Use a water testing kit to check the pH, ammonia, nitrite, and nitrate levels in the tank. Make any necessary adjustments to maintain optimal water conditions.

Cycle the Tank

Cycle the tank to establish beneficial bacteria. This involves adding a source of ammonia and monitoring the water parameters until they stabilize.

Acclimate the Fish

Before introducing your cardinal tetras, acclimate them to the tank’s water. Float the bag containing the fish in the tank for about 15 minutes, gradually adding small amounts of tank water to the bag over the next 15-20 minutes. Finally, release the tetras into the tank and observe them as they settle in.

(If you’ve never setup a fish tank before, then this article, will give you a complete guide from start to finish on how to setup your tank!)

Differences In Male Vs Female

While it may be challenging to differentiate between male and female cardinal tetras just by looking, there are some subtle things to notice.

One of the main differences is in their size. Male cardinal tetras are often slightly smaller and more slender than females, but it’s not always easy to see this until the mating season comes when the females become rounder.

Another thing to notice is the color. Male cardinal tetras usually display brighter and more vibrant colors compared to females, and their red stripe is usually more vivid and stands out.

Sometimes, males have longer fins, especially the one on their back called the dorsal fin. This can be another clue to help tell them apart.

During breeding, there are more noticeable differences. Females have a rounder belly when they’re carrying eggs, while males stay the same size but become more colorful and active as they try to court the females.

It’s important to remember that these differences may not always be obvious, and it can be tricky to tell males from females. So, the best way to know their gender is to observe their behavior during breeding.

Diet

In their natural habitat, cardinal tetras mainly eat small insects, larvae, and tiny organisms found in the water and among plants. To replicate their natural diet, it’s important to provide them with suitable food options in the aquarium.

The main part of their diet should be high-quality flakes or pellet food made for tropical fish. Look for options that contain a good mix of protein, vitamins, and minerals to support their overall health.

And to add variety and extra nutrition, you can also offer them small live or frozen foods. Some popular choices include brine shrimp, bloodworms, daphnia, and mosquito larvae. You can find these foods at pet stores or even grow them at home.

Always remember to feed them small amounts multiple times a day instead of one big meal. This is closer to how they eat in the wild and helps prevent overeating and digestion problems.

Also, make sure to keep an eye on their feeding behavior. Cardinal tetras are active eaters, so if they show little interest in food or seem uninterested, it could be a sign of stress or illness. 

And after feeding, make it a habit to remove any leftover food from the tank. This helps maintain good water quality and prevents potential health issues.

Best Tank Mates for Cardinal Tetras 

Because your Cardinal Tetras are gentle and love to socialize, it’s absolutely important to keep them in tanks with the best tankmates. So, here are some of the most compatible tankmates for your Cardinal Tetras and why they’re great choices.

(If you want to know about the most colorful freshwater fish, here are some great choices!)

Guppies

Firstly, let’s talk about the peaceful guppies. These colorful little swimmers are a great match for cardinal tetras. They share similar personalities and won’t bother each other. Plus, their contrasting colors create a visually stunning display in your aquarium.

Neon Tetras

Next up, we have the charming neon tetras. Like their cardinal cousins, they thrive in a harmonious environment. With their bright blue and red stripes, they’ll create a captivating match of colors with your cardinal tetras. Just make sure you provide enough space for everyone to swim happily.

Panda Corydoras

Moving along, we come across the adorable panda corydoras. These bottom-dwelling cuties are a perfect match for cardinal tetras. They won’t disturb each other, and their patterns make for a visually appealing combination.

Mystery Snails

Now, let’s explore the world of snails, where mystery snails are a popular choice. Not only do they keep the tank clean by munching on algae, but they also make fantastic tank mates for cardinal tetras. Their slow-moving nature won’t bother the active tetras, and they add a unique element to your tank’s beauty.

Platies

With their vibrant colors and easygoing nature, Platies make wonderful companions for cardinal tetras. They need similar water conditions as your Cardinal Tetras to thrive, making them a nice addition to your aquarium.

Zebra Danios

If you’re looking to add some excitement to your tank, introducing some zebra danios could be a great idea! These active swimmers love to move around, creating a lively and energetic display. Also, they’re very friendly, which is why they make excellent tank mates for your cardinal tetras.

Angelfish

If you’re seeking a touch of elegance, consider the graceful angelfish. These majestic creatures can coexist nicely with cardinal tetras as long as your tank is large enough to accommodate their size. Their flowing fins and distinct shape create a captivating contrast to the cardinal tetras’ vibrant colors.

Sparkling Gouramis

For a unique addition to your community tank, check out the famous sparkling gouramis. With their cuteness and shimmering scales, they’ll surely add a touch of magic to any aquarium.

German Blue Rams

Let’s not forget about the stunning German blue Rams. These small, vibrant fish are known for their peaceful nature and eye-catching appearance. They will happily share the tank with cardinal tetras, creating a captivating underwater landscape.

Otocinclus Catfish

Lastly, we have the lovable otocinclus catfish. These little algae eaters are not only beneficial for tank maintenance but also get along well with cardinal tetras. 

Cardinal tetras and all the fish listed above are all great choices for a community tank! However, there are plenty more to choose from! Here are another 50 great choices for your community tank!

Cardinal Tetra Plants

Picking the right plants for your cardinal tetras is also going to help them to feel happy and safe in the tank! As long as the plants are giving them a lot of places to hide though, you can’t really go to wrong!

Java Moss

Java Moss is a popular choice for tetra tanks. It has lush green branches that create a natural and safe environment for your tetras to swim and hide in.

Amazon Sword

The Amazon Sword plant adds elegance to your tank with its broad leaves. It provides shade and a sense of security for your tetras and also helps keep the water clean by absorbing excess nutrients.

Water Wisteria

Water Wisteria is a versatile and low-maintenance plant. It has delicate, feathery leaves that tetras love to swim through. It also helps purify the water, keeping your tank healthy.

Anubias

Anubias is a hardy plant that’s great for beginners. Its dark, leathery leaves create a beautiful contrast in the tank. Tetras enjoy resting and exploring among its broad leaves, using it as a favorite hiding spot.

Java Fern

Java Fern is another popular choice for tetra tanks. Its unique leaves add an interesting touch to your tank. Cardinal tetras appreciate the shade and cover it provides, making them feel comfortable.

Cardinal Tetra Breeding

Let’s explore the process of breeding cardinal tetras. Breeding these beautiful fish can be a rewarding experience, but it requires careful attention to their specific needs.

Creating the Right Conditions

To start breeding cardinal tetras, set up a separate tank with suitable conditions. Increase the water temperature by a few degrees, provide plants or spawning mops, and dim the lights in your tank.

Introducing Males and Females

Add mature cardinal tetras, both males and females, to the breeding tank. Make sure to maintain a ratio of at least three females to one male cardinal tetra to prevent aggression.

Courtship Behavior

Observe your Cardinal tetras’ courtship behavior. Males will display bright colors and perform swimming displays to attract females, and in turn, female tetras will show interest in the males.

Laying Eggs

After successful courtship, the female will lay her eggs on the plants or spawning mops. When this happens, make sure to immediately remove the adult tetras to protect the eggs.

Hatching and Fry Care

The eggs will hatch within 24 to 48 hours. The fry will cling to the plants or spawning mops until they absorb their yolk sacs. Once they start swimming freely, feed them infusoria, liquid fry food, or commercially available fry food.

Water Quality and Care

Maintain good water quality in the breeding tank by regularly changing the water and monitoring its parameters. Use proper filtration to keep the environment clean and stable for the fry’s health and survival.

Gradual Diet Transition

As the fry grow, introduce finely crushed flake food and baby brine shrimp to their diet. Provide hiding places and live plants for them to explore and find shelter.

Patience and Observation

Breeding cardinal tetras can be challenging and may require several attempts. So, be patient and observe their behavior and needs closely to increase the chances of successful breeding.

Cardinal Tetra Common Diseases 

Like any other creature, Cardinal Tetras can catch diseases despite your best efforts to care for them. And when it happens, recognizing the signs and providing the right treatment can help your Cardinal Tetras recover. 

Disease	Symptoms or Causes	Suggested Action or Treatment
Ich	White spots on the body and fins	Raise water temperature, use ich medication
Fin Rot	Ragged or frayed fins	Isolate affected fish, clean tank, use antibiotics or antifungal medication
Swim Bladder Disorder	Difficulty swimming, floating upside down	Feed sinking food, improve water quality
Dropsy	Swollen abdomen, raised scales	Isolate affected fish, use antibiotics or antifungal medication
Mouth Fungus	White or gray patches on the mouth	Isolate affected fish, clean tank, use antifungal medication
Columnaris	White patches on the body, fin erosion	Isolate affected fish, clean tank, use antibiotics or antifungal medication

How Many Cardinal Tetra Can You Keep Together?

To ensure their well-being and natural behavior, it is recommended to keep at least six cardinal tetras together. By having a group of this size, they feel more secure and comfortable, leading to vibrant colors and active behavior.

In contrast, when your Cardinal Tetras are kept in smaller numbers, they may become shy, stressed, and their colors will be duller. By maintaining a group of six or more, you’ll get happier Cardinal Tetras, and a happier tank!

So, always consider the size of your tank when determining the number of tetras to keep. For a group of six cardinal tetras, a minimum tank size of 20 gallons or larger would be suitable.

Keeping a larger group of cardinal tetras can create a beautiful display of colors and movement, but be sure your tank is big enough and your water quality is appropriate for the number of tetras you want to keep.

Facts About Cardinal Tetra

1. Cardinal tetras originate from the Amazon River basin in South America, where they inhabit slow-moving rivers, flooded forests, and blackwater streams.

2. Cardinal Tetras are known for their stunning colors, displaying a combination of shining blue and vibrant red, with a distinctive stripe running from nose to tail.

3. Breeding cardinal tetras can be challenging in a home aquarium. It requires specific water conditions, such as soft and acidic water, along with appropriate spawning sites and attentive care.

4. Cardinal tetras are sensitive to water quality, especially to ammonia and nitrite levels. So, regular monitoring of water parameters and proper filtration are essential for their well-being.

5. Cardinal tetras are popular in aquariums because of their bright colors and calmness. They bring beauty and liveliness to community tanks, making them a favorite among fish enthusiasts.

FAQ

Here are some frequently asked questions that people have about cardinal tetras!

Cardinal Tetra Vs Neon Tetra

Cardinal and neon tetras are popular aquarium species with similar characteristics but notable differences. Cardinal tetras have longer red stripes and are larger, while neon tetras have shorter stripes and aren’t as hardy. Also, generally, Cardinal tetras may require more care to thrive.

Do Cardinal Tetras Need Light?

Like most fish, Cardinal tetras need light in their tank. Light helps simulate their natural environment and keeps them healthy. However, it’s important to find the right balance of light intensity and duration. Dimmer lights can mimic their natural habitat and show off their vibrant colors.

Are Cardinal Tetras Bigger Than Neon Tetras?

Cardinal tetras are slightly larger than neon tetras. Cardinal tetras reach a size of about 2 inches when fully grown, while neon tetras typically reach about 1.5 inches in length.

Are Cardinal Tetras Sensitive?

Cardinal tetras are known to be sensitive fish. They can be more delicate compared to some other fish species, requiring stable conditions and proper care. They are especially sensitive to water quality, like ammonia and nitrite levels. 

However, inbreeding has occurred more and more with a lot of tropical fish. You’ll notice a lot of fish keepers having more luck keeping cardinal tetras vs neon tetras now.

Can Cardinal Tetras Live With Bettas?

Betta fish can easily live with cardinal tetras in a community tank. Just make sure you give them enough space and hiding places in the aquarium to prevent them from feeling stressed.

What’s The Best Breeding Temperature For Cardinal Tetras?

The best temperature for breeding cardinal tetras is around 82ºF. This slightly warmer temperature helps stimulate their breeding behavior and increases the chances of successful breeding.

Do Cardinal Tetras Need A Heater?

Cardinal tetras need a heater in their tank. They come from warm tropical waters, so it’s important to keep their tank at a consistent temperature. Using a heater helps maintain the right temperature for their well-being.

Conclusion

By creating a suitable environment with appropriate tank size, water conditions, and tank mates, you can ensure your Cardinal Tetras’ happiness. And with the right care, your cardinal tetras will thrive and bring so much joy to your aquarium!