If you’re new to fishkeeping, or just new to Tetras, Cardinal Tetras and Neon Tetras might seem like the exact same fish. However, they are two entirely different species of fish. It’s pretty bizarre how closely they resemble each other in my opinion. As confusing as it might seem, it’s actually very easy to tell one from the other.
Cardinal Tetra have a red stripe down their entire body, whereas Neon Tetras only have a red line halfway down their body. Additionally, Cardinal Tetra grow about half an inch larger than Neon Tetra.
In addition to physical differences, this article will also discuss each species specific care requirements.
Cardinal Tetra Overview:
Origin and Habitat
Cardinal Tetras are from the upper Orinoco and Negro Rivers in South America. The water here is extremely soft, warm, and acidic. It’s also densely packed with vegetation, dark substrate, and stained with tannins. Many areas here are also very shallow.
Appearance and Size
Cardinals are known for their more vibrant colors that cover most of their body. In contrast to neons, cardinals, have a deeper more complete blue on the top of their body and the entire bottom of their body is a deep red. Adult Cardinal Tetras reach about a maximum of 2.5 inches.
Water Requirements and Care
Cardinal Tetras require more specific water parameters. They do best with water temperatures between 75-86F (24-27°C), with a pH between 4.5 and 7.5. Soft water is important for this species, they are fairly sensitive and they tend not to do well if the hardness is more than moderate.
Neon Tetra Overview:
Origin and Habitat
Neon Tetras are native to the Amazon River just like Cardinal Tetras, however, they are from different parts. Neon Tetras are found in parts of Colombia, Brazil, and Peru.
They’re a bit more adaptable to water conditions because these conditions vary in the wild. Specifically water clarity, pH, and temperature. Therefore, they tend to be more hardy than Cardinals in this aspect.
Appearance and Size
Neon Tetras don’t get quite as large as Cardinal Tetras, maxing out at around 1.5 inches. The Blue stripe is slightly lower and slightly shorter than Cardinals. The red stripe is the easiest and most basic way to tell them apart. On Neon Tetra, the red stripe starts halfway down their body around the adipose fin, whereas the red stripe on Cardinal Tetra starts at the eye and goes all the way to the caudal fin.
Water Requirements and Care
As mentioned before, because of their varying conditions in the wild, Neon Tetra tend to be less sensitive to water parameters. They do well with water temperatures between 70-78°F (21-25°C) and a pH of 5.0-7.5.
Side-by-Side Comparison
Lifespan
Both species live between 3 to 5 years with proper care and environments. However, without proper care, I would estimate a lifespan of about two years.
Behavior and Tank Compatibility
Both species are non-aggressive schooling fish that should be kept in groups of at least six. If they aren’t kept in schools, they will basically live a life of feeling vulnerable.
Diet
Cardinal and Neon Tetras are both omnivores. Therefore, their diet should be a good mix of foods like flakes, pellets, brine shrimp, blood worms, etc.
Aquarium Setup Tips
A minimum tank size of 20 gallons is recommended for both species, especially Cardinals. You can probably get away with a small school of neon tetras in a 10 gallon.
Both species do best in moderately to heavily planted tanks with plenty of hiding spots. While this is important, it’s also important to give them good clear horizontal swimming space as well.
Cardinal Tetras vs Neon Tetras
The easiest way to tell these species apart is by their red line. Cardinals have a red line from their eye to the caudal fin, Neons have a red line starting in the middle of their body down to the caudal fin.
Being that there’s a very small temperature overlap between each species, I personally don’t think they’re compatible with one another, although you can absolutely get away with it. That’s just my opinion. Cardinal Tetras do great with warmer water fish like Blue Rams, Sterbai Cories, Discus, Rummynose Tetra, etc. In contrast, neon tetras are a staple community fish that are compatible with a much larger choice of tank mates that don’t require as warm of water as Cardinals Tetra.
Now that you’ve learned the difference between Neon Tetras and Cardinal Tetras, you should consider which one will fit best in your tank.
