Green Neon Tetra vs Cardinal Tetra: Species Comparison

Posted by on 08/10/2023


The Cardinal Tetra (scientific name: Paracheirodon axelrodi) hails from the Amazon, where it can be found swimming in the rivers beneath the jungle's canopy. The species is often confused with the Neon Tetra, which is distinguished by a shorter red stripe that stretches horizontally on the fish's body. In Cardinal Tetras, the red stripe spans the entire length of the fish's body, while in Neon Tetras, this red stripe will only stretch to cover about 50% of the fish's body.

Cardinal Tetras will grow to be about 2 inches in length when fully grown, compared to a Neon Tetra, which will reach an adult size of about an inch and a half.



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Cardinal Tetras

The Cardinal Tetra (scientific name: Paracheirodon axelrodi) hails from the Amazon, where it can be found swimming in the rivers beneath the jungle's canopy. The species is often confused with the Neon Tetra, which is distinguished by a shorter red stripe that stretches horizontally on the fish's body. In Cardinal Tetras, the red stripe spans the entire length of the fish's body, while in Neon Tetras, this red stripe will only stretch to cover about 50% of the fish's body.

Image of a Cardinal Tetra
A Cardinal Tetra

Cardinal Tetras will grow to be about 2 inches in length when fully grown, compared to a Neon Tetra, which will reach an adult size of about an inch and a half.

Image of a Neon Tetra
A Neon Tetra, notice the length of the red stripe compared to the Cardinal Tetra

Green Neon Tetras

Contrary to popular belief, Green Neon Tetras (scientific name: Paracheirodon simulans) don't display the Green Neon coloration you would expect from the fish's name. Rather, the fish will demonstrate an iridescent blue coloration that will "color up", meaning, as your aquarium lights turn on, the fish will change colors, showcasing its brightest coloration 20-30 mins after the lights go on.

The Green Neon Tetra is a fantastic schooling fish and has even earned its place on our list of best freshwater schooling fish

Image of a Green Neon Tetra
A Green Neon Tetra

Best for Planted Tanks

If you plan on introducing one of these fish into a planted aquarium, they both make for excellent options. However, we think certain species look better with certain aquascapes.

For planted aquariums that represent an Iwagumi aquascape, or for aquariums that have only green plants, we recommend going with Cardinal Tetras. Their bright blue coloration, combined with their red horizontal stripe will create a beautiful contrast in an all-green planted aquarium. 

However, if your tank represents a Dutch-style aquascape, peppered with red aquatic plants, the Green Neon Tetra is an excellent option. Since these fish do not have the red horizontal stripe seen in Cardinal Tetras, they won't get lost among a backdrop of red aquatic plants, and will easily remain in the center of the spotlight 

Best for Nano Tanks

Smaller-sized fish is the way to go in nano aquariums, and for that the Green Neon Tetra makes an excellent option.

When kept in groups, these fish will form tight schools, swimming in unison. This schooling behavior is highly sought after by hobbyists, and although Cardinal Tetras demonstrate similar behavior, you won't be able to keep as many in a nano tank due to their slightly larger size.

Best for Community Tanks

In freshwater aquariums, snails, shrimp, and even frogs are added to an existing fish tank to create what's known as a community tank. In this configuration, hobbyists will have to juggle the overall care and compatibility between different types of species. When setting up a community tank, fish with a peaceful temperament are often highly desired.

Although Green Neons and Cardinal Tetras are both considered to be peaceful fish, both descend from the same families as piranhas and as such, are active hunters for bite-sized pieces of food. If you're deciding between the two, the Green Neon Tetra is the more peaceful species, and should rarely pick at small inverts, such as baby shrimp and snails. However, if your aquarium has plenty of natural hiding spots, the Cardinal Tetra can also co-exist with other peaceful species. 

Conclusion

The main difference between Cardinal Tetras and Green Neon Tetras is that Cardinals tend to be slightly larger and have a red stripe that extends the full length of their body.

Regardless of which tetra you choose, you'll likely be happy with whatever decision you make. They're excellent fish and an absolute joy to own, and they serve as great beginner fish until the hobbyist is ready to take on a rarer species, such as the sought-after Kerri Blue Emperor Tetra.

Now that we've compared the two, which do you think you'll choose? Let us know in the comments, and be sure to visit our marketplace, where you can find these fish for sale from other hobbyists and trusted breeders.

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Miles Harrison

With over a decade of aquarium experience, Miles can be found writing about saltwater and freshwater aquariums. When he’s not writing about fish, you can find him going for a run or building websites, such as this one!