The Neon and Cardinal Tetras are two very similar-looking fish species that both come from the waterways of South America. With dazzling red and blue colors, they make a bold and striking addition to your tank and are a sure crowd-pleaser no matter what kind of setup you have.
They are also, especially the Neon, some of the most commonly kept fish in aquaria, great for beginners, and very easy to take care of. Because of their ubiquity, you may be forgiven for thinking that one can simply substitute for the other. However, this is very much not the case at all. Read on the find the differences between these two species and which one would suit your aquarium better.
Cardinal Tetra VS Neon Tetra

Ultimately, many of the differences between the Cardinal and Neon Tetras come down to size, sensitivity, and needs in terms of water quality and conditions. However, before we delve into this in more detail, it’s important to understand exactly which factors to consider when choosing between the two species.
Factors To Consider
As stated above, sensitivity and water conditions are the biggest variables between the two species. Therefore, it’s best to consider how you would take these factors into account when setting up your tank. For example, the following factors are generally a good rule as to what to take into account:
1. Your Experience As A Fishkeeper
Make no mistake, when you are breeding fish, or dealing with more sensitive fish, it’s good to be realistic about your experience as a fishkeeper. If you’re a beginner, it’s highly likely you will be better united to the hardier Neon Tetra – something that is explored in further detail below.
Both species are easy to take care of, but there is a difference in the likelihood that problems may arise, especially if it is your first time keeping fish point blank.
2. Your Time Constraints
Similar to your level of experience, time constraints are important to factor in when choosing fish. If you feel you may occasionally be pressed for time, it’s good to opt for fish that are less sensitive and easier to take care of.
3. Your Budget
Budget can sometimes be restricting when choosing fish, and more common species that can be easily bred in captivity tend to be cheaper. It may also be that you don’t live near a specialist aquatics store and you are limited to only what you can find in your local pet shop. In this case, for example, before you set your heart on a shoal of dazzling Cardinal Tetra, it might be that the Neon is a more readily available alternative that can be just as striking and easier to take care of as well.
4. Whether Or Not You Have Kids
Last but not least, even if you have experience keeping fish, if you have kids who will partially be responsible for the aquarium, there are some species that are more suitable. Neons are a very easy kind of Tetra to look after and are in fact one of the species best recommended for children’s aquariums.
Neon Tetra VS Cardinal Tetra: Ease Of Care

As a rule, it’s the Neon Tetra that is marginally easier to care for. However, why is this, and how big is this difference?
If you are an experienced fishkeeper, the difference is negligible. However, if you are a beginner, you may want to opt for the Neon Tetra. This is because they are much hardier and less likely to die from small mistakes. In addition, even though it is not always pleasant to think about, you may occasionally lose some fish.
Therefore, if some of your fish die, it’s easier to find the Neon Tetra in stores to replace them. It’s not a good idea to substitute Cardinal Tetras for Neons in this instance.
Your Experience
Simply put, the Neon Tetra has been bred in captivity for longer and thus as a result is hardier, and can withstand fluctuations in water quality much more easily. This includes the levels of nitrates and nitrites, as well as ammonia and general dirty water. However, this does not mean you should neglect your fish. It simply means if you don’t get the water conditions perfect at first – and this is something that comes with time and effort – it’s much more likely that Neon Tetras will withstand this without getting ill, as opposed to Cardinal Tetras.
Remember that nitrates, nitrites, and ammonia should always be kept at zero! It’s never a good idea to try and run a tank without a filter, either. Fish can sometimes survive like this, but they will never thrive, and it’s unlikely they will reach their full lifespan.
Author’s Note: Overall, Neon Tetras have been bred in captivity for longer and as a result of this, they are also much bolder. They won’t be skittish or get scared off when you approach the tank to feed them in the same way a shoal of Cardinal Tetras can sometimes be. This also makes them more enticing for beginners.
Cardinal Or Neon Tetra: Tank Conditions

1. Tank Size
Tank size is a very important factor in choosing whether to go for a Neon vs Cardinal Tetra. This is especially so if you have a small tank of 10 or twenty gallons. Simply put if you have a small 20-gallon (76 liter) aquarium it will need cleaning more often and Neon Tetras are more likely to withstand the water conditions there as dirt can build up faster. If you have a larger tank such as a 30-gallon (114 liter) aquarium, even with a tankmate, you begin to have more leeway. The water does not become dirty so quickly, and thus even a more sensitive species like the Cardinal Tetras can survive.
There is one exception here – if you have a nano aquarium such as 10 gallons, or one where there is an odd shape or not a huge amount of surface area, you may want to consider the Cardinal Tetra. This is because they are marginally smaller than the Neon Tetras.
As a result, you can see there are no hard and fast rules. All tanks are different and in the end, it’s up to you to judge the right environment for your fish. However, the smaller size of the Cardinal Tetra does mean you can keep a bigger shoal in a smaller tank if you want.
2. Tankmates
Another factor to take into account is fish temperament and tankmates. Cardinal Tetras are one species that you can keep in a shoal without any other tankmates. That doesn’t mean you can keep fish by themselves. That just means they are a stunning species to keep as the centerpiece to do with their small size and more nervous habit. In a tank with a larger tankmate, they can sometimes get overshadowed.
Neon Tetras, meanwhile, can hold their own in a tank with other fish due to their bolder temperament. That’s not to say that the Cardinal Tetra can’t be added to a larger community tank such as with Angelfish. It’s just a dynamic to consider if you want your fish to really be able to express their full behavior.
Author’s Note: Are you into color changes? The Neon Tetra famously changes color depending on the amount of light – specifically, it changes the color of it’s Neon stripe. If you’re looking for this phenomenon, then this is the fish for you.
- Can Neon And Cardinal Tetras Be Kept Together?
There’s no reason why you can’t keep Neon and Cardinal Tetras together. However, it’s not often done for quite a few reasons, most of which relate to the difficulty in telling them apart, and interspecies competition.
There’s not a lot of research into the dynamics that happen when fish encounter other fish that look like them but the challenges in telling the species apart even for breeding purposes, or if you have to identify and isolate a sick fish, can mean keeping these two lookalikes together can be more trouble than it is worth.
3. Filtration And Planting
Another consideration for the Neon Tetras’ greater hardiness is your filtration and planting. In the wild Cardinal Tetras live in fast-flowing streams that are rich with vegetation, generally in tributaries and headwaters of the amazon.
As a more sensitive species that is generally captured from the wild they need somewhat analogous conditions to thrive in captivity. Thus, they need a good filter and plenty of plants with added driftwood and stones to recreate their natural habitat. They also are adapted to soft, acidic habitats. In fact, the adidtion of driftwood in captivity can help lower the pH of your tank to mimic this!
Neon Tetras on the other hand can survive in a wider variety of habitats. Therefore, if you don’t have the budget for plants and driftwood, or you don’t like the look of a naturalistic tank, it’s better to go with the Neon Tetra.
4. Tank Aquascape
Are you interested in Aquascape? While Neon Tetras can be great for a children’s tank, aquascaping is a serious hobby that is popular amongst professional aquarists and involves the creation of naturalistic underwater landscapes. One of the forms of the practice comes from Japan, where it is known as iwagumi, and is cherished for its beauty and simplicity.
If you are keen to have a more natural tank where the focus is a much on the plants, substrate, and ornaments as it is on the fish, a shoal of the slightly smaller and more timid Cardinal Tetra can be a great choice. The more skittish behavior of this fish can often mimic a natural river environment and their unobtrusive size means they do not overshadow the scenery.
Neon or Cardinal Tetra: Breeding

Do you want to breed your fish? This is one of the main areas in which the differences between the two species become very significant. In short, you may have more luck with breeding Neon Tetras than with Cardinal Tetras, especially if you are new to breeding fish.
However, like everything with keeping fish, there is no straightforward answer and there are also significant differences in fish fertility.
1. Breeding Neon Tetra
Breeding Neon Tetra is, in all honesty, fairy easier than breeding Cardinal Tetras. If you want to breed fish but don’t have a lot of experience, go for Neon Tetra. Their hardiness and ability to thrive mean you are less likely to lose fish or fry. Their tolerance for a wide range of conditions and their higher threshold for stress means you are more likely to be able to get them to breed. This is especially true if you don’t have a large breeding tank.
2. Neon Tetra Fertility
There is one flipside to the Neon Tetra’s history in captivity. This fish is so ubiquitous it is sometime shard to tell the quality or your supplier. This means that if you get fish from a substandard supplier that does not pay attention to the parentage of the fry, conditions they are bred in, or breeds fish that are sick or otherwise damaged in some way, you may find you can’t get your Neon Tetra to breed.
That’s not to say all Neon Tetras are cheaply bred, and there are many reputable suppliers that really take care of their fish. It just means due to how common this fish is and the fact it is bred din captivity as opposed to taken from the wild, there is a significantly higher chance that pet store Neon Tetra may be infertile or have some genetic issues down the line.
Bottom Line
Overall, whether you go for Neon or Cardinal Tetras makes most of a difference if you have a very small tank, or if you are a beginner. Otherwise, when you are a more experienced fishkeeper or if you are simply adding a school of small fish to a larger community tank, the two can, in essence, be substituted for each other due to their similar personalities and needs. Therefore, if your pet shop does not have the less common Cardinal Tetra, Neon Tetras can be a great alternative.
However, for fishkeepers who are worried about hardiness, or who have particular needs, this article should have outlined some of the main differences and how they affect any community aquarium.