Introduction

Are you looking to make your aquarium pop with color? Do you want to see dynamic activity taking place in the waters of your tank?  If so, there are two species from the tetra family that will check those boxes, plus more.

The fish I’m referring to are the neon and the cardinal tetra. Both fish are inexpensive and are suitable for the beginner and advanced aquarist. But while these species are closely related, there are some notable differences between them, which I’ll talk about below.

Neon Tetra Overview

Let’s start with the neon tetra and its characteristics.

Physical Description

Neon tetras average one inch in length, and they have blue and red stripes against a steely grey background. Their heads are often colored blue while their tails are often red in color.

Natural Habitat and Behavior

Neon tetras (Paracheirodon innesi) are found in slow-moving blackwaters in South America. A schooling fish, neon tetras are found in the middle of the water columns of river tributaries that run through forested areas.  

The waters that they inhabit are brownish in color. This is due to the tannins that leach from the fallen leaves that land in the water. In the wild, neon tetras feed on plant matter, aquatic worms, and small crustaceans.

Care Requirements

Tank Size

As neon tetras are schooling fish, you should keep them in a group of at least six fish. You can keep up to six fish in a 10-gallon aquarium. However, a 20-gallon aquarium is preferable. It’ll give them more room to swim while making water parameters more manageable. 

Remember, the larger the aquarium you have, the less chance of experiencing a build-up in ammonia, nitrites, and nitrates. Elongated tanks should be used to maximize swimming space.

🐠 Read our ultimate guide to setting up a fish tank where we go more in-depth on everything you need to know for a successful, thriving aquarium.

Water Quality

The water parameters for neon tetras should be as follows:

• Temperature: Between 68-77 degrees Fahrenheit.
• pH: Between 5.0-8.0. 
• Water hardness: Between 3-25 dGH. 

Feeding

The neon tetra diet should consist of quality flake food and pellets, supplemented with freeze-dried brine shrimp, bloodworms, or daphnia. To keep these fish healthy and at their best coloration, it is important to provide them with a balanced diet.

When feeding neon tetras, feed them only what they can consume in a few minutes. You can feed your fish twice a day.  

Tank Mates

Neon tetras are peaceful fish and can be kept in a community tank. The best tank mates for them are:

• Mollies
• Cardinal tetras
• Platys
• Corydoras catfish

🐠Are neon tetras compatible with betta fish? Find out here.

Notable Characteristics

Neon tetras are widely bred so most pet store stock captive-bred fish. Because of captive breeding, there are a wide variety of color morphs that are available. 

Cardinal Tetra Overview

Now, let’s look at the cardinal tetra and its characteristics.

Physical Description

Cardinal tetras are larger in size than neon tetras, with an average size of two inches in length. They also have a red and blue stripe and a chocolate brown colored dorsal area.

Natural Habitat and Behavior

As with neon tetras, cardinal tetras (Paracheirodon axelrodi) are also found in South America. However, their range is restricted to the Orinoco River and the upper Rio Negro. Like neon tetras, cardinal tetras also are found in large schools.

Care Requirements

Tank Size

Cardinal tetras are schooling fish and should be kept in groups. You can keep up to six cardinal tetras in a twenty-gallon aquarium. For each additional fish, add two gallons. Like with neon tetras, elongated tanks should be used to maximize swimming space.

Water Quality

The water parameters for cardinal tetras should be as follows:

• Temperature: Between 73-81 degrees Fahrenheit.
• pH: Between 4.5-7.0
• Water hardness: Between 2-8 dGH. 

Feeding

Cardinal tetras can be fed the same diet as neon tetras of quality flake food and pellets, supplemented with freeze-dried brine shrimp, bloodworms, or daphnia. Feed them only what they can consume in a few minutes, twice a day. 

Tank Mates

Cardinal tetras do well in a community tank. However, you should avoid keeping other fish species that are slow-moving and that have flowing fins (such as in certain mollie, guppie, and swordtail species) which cardinal tetras may nip at.

Recommended tank mates include:

• Neon tetras
• Dwarf gourami
• Neon tetras

Notable Characteristics

Cardinal tetras tend to be difficult to breed, which is why most pet store specimens are wild-caught.

Neon vs Cardinal Tetra: Similarities and Differences

The following is a comparison between the two species regarding their characteristics and their care:

Water Parameters

The two species have similar water parameter requirements. However, neon tetras are more tolerant to changes in water parameters.

Cardinal tetras have a lower tolerance to water temperatures below 73 degrees Fahrenheit. They’re also less tolerant to high levels of nitrates, ammonia, and nitrites.

Appearance

Though neon tetras and cardinal tetras have a similar appearance, the neon tetra is smaller than the cardinal tetra. Also, the red and blue stripe doesn’t run the full length of the body in the neon tetra while it does in the cardinal tetra.

Size

Cardinal tetras are larger, with an average length of two inches while neon tetras normally reach a length of one inch.

Captive Breeding

Neon tetras are routinely bred in captivity, making them less expensive than cardinal tetras, which are difficult to breed and are normally wild-caught.

Tank Setup

Both species are native to the black waters of South America. These waters are characterized by subdued lighting and lush plant growth. When setting up the aquarium, I recommend that you avoid bright lighting and provide plenty of plants.

How To Tell the Difference Between a Neon Tetra and Cardinal Tetra

The two species are similar in appearance, but there are subtle differences. Besides being larger than neon tetras, cardinal tetras have slightly different markings.

The blue and red stripes in cardinal tetras extend across the full length of the body.  The blue and red stripes in the neon tetras fall short of running the full length.

Is the Cardinal Tetra A Neon Tetra?

Cardinal and neon tetras are separate species but belong to the same family of fish, Characidae. Both species occupy the same habitat and have the same behaviors. The only difference is their distribution.

While both species are found in South America, cardinal tetras are found in the Orinoco, Rio Negro, Venezuela, and Brazil.

Neon tetras are found in Rio Taquari, Pantanal of Mato, the Paraguay River Basin, Grosso do Sul, and Brazil.

Choosing the Right Tetra for Your Aquarium

Now that we’ve compared the two species, the next question you may be asking is, “Which species is right for me?” The following is a summary that should help you decide.

Aquarium Experience

If you’re new to keeping aquariums, I recommend that you go with the neon tetra. They’re hardier fish and can tolerate a wider range of water parameters.

Compatibility

Both species are schooling fish and have a gentle personality. For this reason, both will do well in a community tank. Good tank mates include:

• Mollies
• Platys
• Corydoras catfish.
• Dwarf gouramis

Breeding

If you plan to breed fish, neon tetras are the fish that you want to go with. Unlike neon tetras, cardinal tetras are very difficult to breed.

Visual Appeal

Though both species are beautifully colored, cardinal tetras tend to have more vivid colors.

Are Cardinal Tetras Easier to Care For Than Neon Tetras?

Cardinal tetras are not as easy to keep as neon tetras. The reason for this is that cardinal tetras are not as tolerant to changes in the water parameters as neon tetras. Neon tetras are more forgiving if the water parameters move beyond the optimal range.

Care and Maintenance

The following are some general care tips for both fish species:

Water Parameters

The water parameters for these two species are overlapping, so I recommend that you keep the tank water in that sweet spot where the water requirements for both species meet.

In their natural habitat, neon tetras live in water that is slightly acidic. The pH should be between 5.0-8.0 while the temperature should be kept between 68-77 degrees Fahrenheit. Water quality should be between 3-25 dGH.

Cardinal tetras should be kept at a pH between 4.-7.0 with a temperature between 73-81 degrees Fahrenheit.  The water hardness should be between 2-8 dGH.

Given this data, the ideal water parameters for keeping both species together would as follows:

• pH: 5.0-7.0
• Temperature: 73-77 degrees Fahrenheit.
• Water hardness: 3-8 dGH.

Filtration

Both neon tetras and cardinal tetras are small fish, so they don’t produce much waste, also known as bioload. Given this, the criteria you’ll want to look for when selecting a filter is its ability to handle the water volume of your tank. This can be determined by the filter’s GPH rating (gallons per hour). Choose a filter that can handle four times the volume of your tank.

Lighting and Décor

In their natural habitat, both species live in slow-moving streams that contain an abundance of organic matter. These parameters lead to murky water. For this reason, I encourage you to provide soft lighting for these fish.

Also, reserve some areas of the tank where you can provide dense vegetation. If you decide to use live plants, hornworts, and java moss are good choices. Leave the rest of the aquarium open so that your fish can swim freely.

Aquarium Maintenance

The most important thing about aquarium maintenance is that you perform partial water changes on a regular basis. All animals produce waste and uneaten food  accumulates quickly

With aquatic animals, the waste accumulates in the water and produces nitrites, nitrates, and ammonia, which can reach toxic levels. To keep the water quality at safe levels, do a 25% water change weekly.  

Before you introduce fish to a newly established aquarium it’s important that you first check that the aquarium has cycled, meaning that there are no nitrites or ammonia in the water and that the nitrate level is low.

You can determine this by using a water testing kit that you can get at most pet or tropical fish stores.

Feeding

Both species are omnivorous, though they’re predatory in their natural habitat. They hunt slow-moving invertebrates such as insect larvae, worms, and daphnia. 

Because of this, you’ll want to feed them quality flake food that’s protein-rich.  Avoid purchasing flake food that lists soy, corn, or potato starch as the first few ingredients.

You can supplement their diet with freeze-dried brine shrimp, daphnia, and tubifex worms.

As mentioned previously, feed them daily but don’t feed them more than they can consume in two minutes.

Can Neon and Cardinal Tetras Live Together?

Both species can exist together as they have similar care requirements. However, neon tetras can tolerate a wider swing in water parameters than cardinal tetras can. Because of this, be sure to maintain the water parameters mentioned above. 

Both Tetras Make a Wonderful Aquarium Addition

Both neon and cardinal tetras are vividly colored and easy to care for. While both species are similar, the neon tetra is more tolerant to changes in water parameters.

Also, most neon tetras are commercially bred while cardinal tetras are difficult to breed. As a result, you’ll most likely be buying caught specimens. 

I hope you enjoyed this article and now understand the differences between neon and cardinal tetras. Please be sure to share this article with your fishkeeping friends.