Cardinal Tetra vs Neon Tetra: Differences | Aquascape Addiction

Cardinal Tetra vs Neon Tetra: Differences

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A detailed comparison of the Cardinal Tetra vs Neon Tetra, if you are not sure which is best for your tank then this will help you make an informed decision.

Cardinal Tetra vs Neon Tetra: Differences

If you like small, peaceful, and brightly colored fish, you might have looked into getting some tetras. However, there are lots of different tetra varieties to choose from, with the neon tetra and the cardinal tetra being two of the most popular options.

Let’s do a little cardinal tetra vs neon tetra comparison so you can make an informed choice in terms of which fish is better for your home aquarium.

Neon Tetra

a neon Tetra fish


The neon tetra fish originates from the Amazon jungle and can be found throughout many countries in South America. It is a freshwater fish that belongs to the characidae family.

It’s a good community fish, with over 2 million of them being sold per month in the US alone.

Size, Appearance, & Lifespan

What really stands out about the neon tetra is its awesome coloration, and one of the first things which people tend to notice is the dazzling turquoise line that stretches from right under its eye to the front of the tail.

You will also notice that the neon tetra has a bright red line on its side that starts at the middle of the body and runs down to the caudal fin.

The color combination makes them extremely recognizable, and it is though that they have these bright iridescent colors in order so that neon tetras can locate each other in murky waters.

These fish have a body that resembles a spindle with a rounded nose. At the very most, the neon tetra can grow to 2.5 inches in length, but they usually top out at around 1.5 inches long.

In terms of lifespan, the maximum age for the neon tetra is 8 years, but generally speaking they will top out at 5 years of age.

Tank Size & Habitat

Now, in terms of tank size, the minimum size for a small school of neon tetras, so about 7 or 8 fish, is 10 gallons.

However, what you need to know is that it is recommended that neon tetras be kept in schools of at least 15 fish, and for this amount of fish, you will want a tank of 20 gallons at the least.

The most important things to remember when it comes to recreating the natural habitat of the neon tetra is that they always live in heavily vegetated areas, characterized by fairly low light levels, and slow moving waters.

You want to have a lot of live plants in a neon tetra tank, along with some rocks, and several pieces of driftwood too. Although a bit of light is required for them, these fish are used to darker conditions, so nothing special is required in terms of lighting.

Water Conditions

When it comes to water conditions, your average neon tetra can survive just fine in waters between 70 and 81 degrees Fahrenheit, so you will most likely need to get a heater for the tank (more on temperature over at this article). Moreover, in terms of pH level, between 6.0 and 7.0 will do just fine, and the water should be fairly soft, under 10 dGH.

What is nice about neon tetras is that they have a small bio load and they don’t produce much waste, so although you do want to have a filtration unit for them, it also does not have to be anything overly special.


Neon tetras in the wild are omnivores, so they will eat both small animals and insects, as well as plant matter too. They are not picky eaters and will eat more or less anything you give them, as long as they can fit it in their mouths (for our food suggestions, see this article).

They will often snack on algae, and maybe even on some of the plants in your tank. Neon tetras will eat both flakes and pellets, plus you can give them Tubifex worms, brine shrimp, blood worms, and daphnia too.

Some boiled and shelled peas can be given to them as well. However, just keep in mind that they are small fish, so all food needs to be in very small pieces.

Compatibility & Behaviour

What’s also nice about the neon tetra is that it is a very peaceful fish. It’s peaceful, it’s not territorial, and it’s not aggressive, which makes it a great type of fish for a community tank.

However, just beware that much larger and more aggressive fish may pick on these little guys.

Cardinal Tetra

a Cardinal Tetra fish

As you will notice, the cardinal tetra is very similar to the neon tetra, with small differences in appearance, as well as some stricter care rules.

The cardinal tetra is slightly more difficult to care for than the neon tetra.


The cardinal tetra can also be found in many South American countries, mainly in Brazil, Colombia, and Venezuela, so the northern parts of South America.

They can be found in both the Amazon rainforest as well as other smaller rainforests all throughout this area. Keep in mind that the cardinal tetra is also sometimes referred to as the red neon tetra.

Size, Appearance, & Lifespan

In terms of the appearance, the cardinal tetra does look similar to the neon tetra, but with a whole lot more red. The cardinal tetra does feature that same neon blue-turquoise stripe running from the eye to the tail, but unlike the neon tetra, the cardinal tetra has much more red on its side, all the way from that blue stripe down to the white underbelly.

What you need to know here is that this red band on the cardinal tetra runs from its face to tail, whereas with the neon tetra, it starts only halfway along the body towards the back. Other than that, neon tetras and cardinal tetras do have that same spindle body shape with a rounded nose.

They are also roughly the same size, although cardinal tetras may be a bit smaller. They grow to a maximum of 2 inches in length, but are usually between 1.25 and 1.5 inches long. Like neon tetras, they will usually live to around 5 years in captivity.

Tank Size & Habitat

In terms of the tank size, the requirements for the cardinal tetra are pretty much the same as for the neon tetra. These fish should ideally be kept in schools of 15, and for this amount of fish, you want an aquarium that is at least 20 gallons, although something slightly larger, such as a 25 gallon tank, is probably better.

Now, these fish are used to the same waters as neon tetras, which means you should provide them with very slow moving waters, a tank that is very heavily vegetated with live plants, some rocks, and several pieces of hollow driftwood too.

They don’t need all that much light, as they are also used to murky waters, but you do still want to get a small aquarium light, something that can provide the cardinal tetras with around 2 watts of light per gallon of water.

As with neon tetras, you do want to provide them a bit of an open swimming space in the center of the tank.

Water Conditions

This is where things do get a little trickier, because unlike neon tetras which will do fine in a variety of water conditions, cardinal tetras have stricter requirements than neon tetras when it comes to temperature, pH, and water hardness.

The water temperature for a cardinal tetra needs to be between 73 and 81 degrees Fahrenheit, with a pH level between 4.2 and 6.2, and a water hardness level under 4 dGH. No, cardinal tetras don’t have a huge bio load, but a good 3 stage filtration unit will still serve them well.


When it comes to feeding, the cardinal tetra requires its diet to consist of about 75% high quality flakes, as these fish need a lot of vitamins. They are omnivores, so you can go for flakes that have a fairly high protein content, but they should also contain plant matter.

You can give them Tubifex worms, brine shrimp, blood worms, and daphnia too. Just remember that all food needs to small enough for their tiny mouths to eat.

Compatibility & Behaviour

Just like the neon tetra, the cardinal tetra is a non-aggressive and non-territorial schooling fish, a peaceful fish that makes for a good community tank mate. As long as they are not kept with much larger and more aggressive fish, they will do just fine.

You definitely don’t want to keep them with any fish that are known for eating smaller slim bodied fish.


At the end of the day, you do have a choice to make here. On one hand, the neon tetra is a bit easier to care for, but on the other hand, the cardinal tetra does look a bit cooler.

With that being said, there if you do it right and keep the water conditions ideal to suit both types of fish, there is no reason why you cannot keep both neon and cardinal tetras in the same community tank (we have covered the other different types of Tetras over here).

Photo credits: The Repilarium& Brian Gratwicke (Flickr CC).