Neon Tetras vs Cardinal Tetras – What’s The Difference?

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When you’re trying to decide if you’re looking at a Neon Tetra vs Cardinal Tetra, it’s hard to tell the two apart unless you know what you’re looking for.

Both are schooling (or more accurately, shoaling) fish that are colored almost identically. They look the same, they behave the same, they even eat the same! However, once you know what you’re looking for it’s easy to tell them apart. Read on to find out more.

Note: Both Neon and Cardinal Tetras make great additions to a community tank due to their peaceful nature. Because of their instinctive group behavior it’s important to keep these fish in groups of 10 or more, but always make sure you have a large enough tank for this many Tetras.

What is the difference between Neon Tetras and Cardinal Tetras?

Neon Tetras and Cardinal Tetras look almost identical. To tell the difference, look for the red stripe down the side of the fish. If it runs all the way from head to tail you have a Cardinal, if it only goes half way it’s a Neon.

There are also subtle differences in size and shape, in that Cardinals are slightly larger while Neons are smaller and more slender. Cardinals prefer slightly more alkaline water than Neons, who are most comfortable at neutral pH.

Interestingly, Cardinal Tetras are notoriously difficult to breed in captivity, which is where they differ from Neon Tetras who are bred in huge volumes rather than being wild-caught like Cardinals. This is why Neon Tetras are cheaper to buy at between $1-$2, while Cardinals generally cost double this price.

Are Cardinal Tetras more hardy than Neon Tetras?

While the two fish are very similar in appearance, Cardinal Tetras tend to be much more hardy than Neon Tetras. Once they are acclimated, they succumb to illness much less than Neons and tend to live longer.

Cardinals do have a more narrow range of tolerance when it comes to pH so the closer to 6.0 you can get your water the happier they’ll be. They also need much lower general hardness than the Neon, which can tolerate up to 10 dGH while Cardinals may struggle above 6 dGH.

Despite the above, if the tank parameters are at the optimal levels you’ll generally find that Cardinals are the more hardy fish.

Which is better, Neon or Cardinal Tetra?

Cardinal Tetras have become just as popular as Neon Tetras in recent years, if not more so. Their colors tend to be more vibrant, they’re more hardy than Neons so they last longer, and they’re also slightly larger, if that makes a difference to your preference.

Personally, I’m Team Cardinal. I have both in my community tank and not only do I prefer the appearance of the slightly larger Cardinals, but I’m also currently treating one of my Neons for Cottonmouth. My Cardinals, on the other hand, have never shown any signs of illness.

My Neon Tetra with Cottonmouth (AKA Cotton Wool Disease)

Can Cardinal Tetra mix with Neon Tetra?

Cardinal Tetras and Neon Tetras can mix together in the same tank with no problems whatsoever. They’re very similar fish which are identical in temperament and diet, and thrive in similar water conditions. They’ll even shoal together when conditions are right!

Confession time – when I bought my Cardinals and Neons they were being kept in the same tank at my local fish store and sold as the same species. I certainly didn’t know the difference at the time (and neither did the store apparently!) and they’ve always been just fine mixing as one large group.

Read more: Neon Tetra Tank Mates: 45 Ideal Choices (And 3 To Avoid!)

Will Neons and Cardinals school together?

Neon and Cardinal Tetras are shoaling (not schooling) fish who will shoal together if the conditions are right. Tetras naturally group together to achieve safety in numbers, so if their individual groups aren’t big enough then some different Tetra species often school/shoal together.

However, it’s not uncommon for Neon and Cardinal Tetras to swim around the tank alone if they don’t feel threatened. While this can be disappointing, don’t worry if your Tetras aren’t schooling as this just means you’re doing a great job and that your fish feel safe enough to explore away from the group!

Read more: Neon Tetras Not Schooling? Here’s Why & What To Do Next

Summary

Cardinal and Neon Tetras are so similar that they’re often assumed to be the same fish, which I was guilty of when I first bought mine!

The main difference is the appearance of the two fish in that the slightly larger Cardinals have a red stripe down the full length of their body whereas the smaller Neons only have this strip half way down.

As mentioned above, I personally prefer the look of Cardinals, which just seem to have sharper, more vibrant coloration. They’re also a more hardy fish that’s less likely to die, provided the water conditions are right for their sensitive nature.

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