Neon Tetra vs Cardinal Tetra: What is the Difference?


Neon Tetra vs Cardinal Tetra (sourceCC BY-SA 4.0)

Studies show that Americans alone own about 139.3 million freshwater fish.

Clearly, many people are in love with keeping ornamental fish, which is mostly because of the benefits they offer. What’s more, most freshwater fish are small and peaceful, making them one of the easiest pets to look after.

But amongst all the types of fish kept out there, tetras stand out as one of the most popular species. Especially the neon tetras and cardinal tetras. As such, understanding the differences between these two tetras will help you make an informed decision when it comes to choosing the best fish species for your home aquarium.

So check out the guide below:

Neon Tetra

Scientifically known as Paracheirodon innesi, the Neon Tetra is species of fish native to the fresh waters of South America.

This fish actually falls under the Characidae family, and it’s an excellent community fish, considering that over 2 million of them get sold every month in the US. If anything, most of the neon tetra available in the market get bred in captivity.

Neon Tetra Behavior

Neon tetras are non-aggressive and peaceful fish that love to spend their time in schools. They also prefer swimming in the middle water column of your aquarium.

What’s more, neon tetras have a lifespan of around eight years when living in the wild and about 5 years in aquariums.

Appearance of Neon Tetras


Neon Tetras (wikipediaCC BY-SA 4.0)

The first thing that draws most people to neon tetras is their sensational colouring. They have a turquoise blue line stretching from their adipose fins (the small rounded fin between the dorsal fin and the tail) up to their eyes.

On top of the unique blue colouration, neon tetras have a red stripe running from their caudal fins up to the middles of their bodies. This colour combination makes them easily recognizable even by amateur fish hobbyists. Interestingly, neon tetras can also assume a transparent appearance, which helps hide from predators.

Their red and blue iridescent hue also fades when they are sick or sleeping. Other than the colours, neon tetras have a rounded nose as well as a spindle-like body. Not to mention that their large eyes account for the majority of their heads.

Additionally, a neon tetra fish can grow to a maximum size of 2.5 inches long. However, the average size of aquarium neon tetras is about 1.5 inches, with females being somewhat shorter.

Neon Tetra Tank Requirements and Habitat

Neon tetras originated from the rivers around Colombia, Peru, and Brazil, where the waters flow thick forests whose dense canopies block lots of natural daylight. These waters are also dark because of the many fallen vegetation, tree roots, and leaves.

And since they prefer living in schools, they have mutated to adopt a vivid colouration that helps them spot their fellow fish when swimming in the dark murky waters.

In the wild environment, you can find the largest gathering of neon tetras around within the Amazon River basin.

It’s advisable to replicate such a natural environment in your aquarium before keeping neon tetras. This includes heavily planting the aquarium and using driftwood to create more darkness and shade for them. Other tanks conditions for keeping neon tetras include:

  • An established, mature tank and not a newly cycled tank. This is to avoid killing the fish because of changes in water chemistry.
  • A tank size of not less than 10 gallons. Although the 20-gallon one is more ideal.
  • The water temperature should range from 70 º F to 81º F, while the pH should not fall below 6.0 or rise above 7.0. In other words, tetras will thrive best in soft water.
  • 2 watts per gallon of subdued lighting.
  • A small filtering system because tetras produce a small amount of bioload.
  • A 25 per cent water change every week

Neon Tetra Diet and Feeding

Wild neon tetras are omnivores and so they feed on insects, small animals, and plant matter.

Most aquarium tetras aren’t picky eaters and can feast almost anything you feed them as long as it fits their mouths. They will mostly snack the plants on your aquarium, including algae, but they can also consume pellets, flakes, blood worms, brine shrimp, and daphnia.

Also, it’s advisable to feed young neon tetras twice a day and an amount they can consume in three minutes max. Once they mature, reduce the frequency of feeding them to once a day, but maintain the three-minute rule.

Neon Tetra Tank Mates

It’s important to place neon tetras together with other fish species that aren’t large enough to eat them.

Thus, go for peaceful bottom dwellers like;

  • Gouramis (Avoid the Opaline, Giant, and Pearl)
  • Barbs
  • Small Catfish
  • Dwarf Cichlids
  • Live-bearers

One rule of thumb to follow when searching for neon tetra tank mates is seeing whether the fish has a mouth that’s large enough to feed on tetras.

Neon Tetra Sexual Difference

Females have a rounder body, while males are more slender.

And because males have a more flat stomach, the blue stripe usually appears straight. With females, the blue strip is somewhat bent because of their round belly.

Breeding Neon Tetras

When it comes to breeding, neon tetras need specific water conditions to trigger mating.

So it’s best to invest in a separate breeder tank because you need slightly different water to what you use in your main tank. The pH level should range from 5 to 6, while the temperature should be about 75 °F.

Tetras are usually egg scatters, meaning that the females lay their eggs and then the males fertilize them. After the eggs hatch, you ought to remove the parent fishes from the breeder tank to ensure they don’t feed on the young ones.

Cardinal Tetra

Scientifically known as Paracheirodon axelrodi, the cardinal tetra is fish that’s native to the fresh waters of upper Negro and Orinoco Rivers in South America.

Cardinal tetras prefer shaded areas with extremely clear standing or slow-moving waters. That’s why in the wild, they mostly live in waterways covered with dense rainforests that allow a little light to pass through.

And even though the cardinal tetra is popular, it’s not widespread like the neon tetra. This is mainly because up until recently, this species of fish was challenging to breed in captivity. But now many people learned to produce this fish.

Cardinal Tetra Behavior

Cardinal tetras love to spend their time extremely large schools that can number up to a hundred fish.

They live in shoals and mostly in the mid-level waters of a tank. Cardinal tetras are also quite peaceful fishes that will get along with all other peaceful species. And while they love staying in large schools, you can keep them in small groups of not less than five. But that increases the risk of your tetras getting stressed out and dying.

A large school goes a long way in making your fish more relaxed and secure. So try to keep at least 10 neon tetras together so that you boost their coloration.

Appearance of Cardinal Tetras


Cardinal Tetra (sourceCC BY-SA 4.0)

The colour patterns of neon tetras often make many people confuse them with neon tetras.

They have a neon blue stripe running from the tail up to the nose. Below the neon blue strip is a commanding red strip. This red colouration into part of the otherwise transparent tail. Other cardinal tetra fins are also transparent, while the underbelly features a soft white colour.

In terms of colouring, one major difference between the cardinal tetra and neon tetra is that the former’s red stripe extends through its entire length, while the latter’s runs only from its mid-body to the tail.

Cardinal Tetra Tank Requirements

Since they are black water fishes, cardinal tetras won’t do well in extremely brightly lit tanks.

It’s therefore paramount to install a dim lighting system as well as dark coloured substrate like tangled roots or pieces of driftwood. You can also add dry leaves to naturally colour the water. By the same token, ensure that the tank is mature with soft acidic water as well as stable water chemistry.

Cardinal tetras do well in an environment with a pH that’s below 6. Also, the water hardness shouldn’t be above 4 dGH. If you keep this fish, water in an environment with high mineral content, high chances are it will have poor health and ultimately a shortened lifespan.

The tank water temperatures should range from 73ºF to 81ºF. In as much as cardinal tetras require hiding places, just provide a few so that they can have plenty of open swimming area. This also means that place them in at least a 20-gallon tank, if not a 25-gallon one.

Generally, cardinal tetras thrive in a similar environment to that of neon tetras. Install a tank with slow-moving waters as well as some rocks, a few pieces of hallow driftwood, and live plants.

Even so, neon tetras thrive in different water conditions, unlike cardinal tetras, which require aquarists to adhere to strict requirements.

Cardinal Tetra Diet and Feeding

Just like the neon tetra, the cardinal tetra is an omnivorous species that accepts many kinds of foods.

Furthermore, cardinal tetras require high vitamin meals so it’s crucial to feed them foods like quality flakes. These fishes also love frozen and live foods, but if they eat them excessively they will reject other foods later on.

It’s best to feed young cardinal tetras several times a day with offering they can consume in three minutes. For adults, you can feed them twice a day with meals they will eat in five minutes. Remember to feed them servings that are small enough to fit their mouths.

Cardinal Tetra Tank Mates

Cardinal Tetras will do well together with other peaceful and small fish like

  • Loricaiids
  • small Rasboras
  • dwarf cichlids
  • other small tetras

Additionally, you can put them together with bottom-level species such as snails, crabs, or shrimp.

Cardinal Tetra Sexual Differences

The females and males of these species have a few clear differences. Females have a deeper body featuring a rounder belly. On the other hand, males appear more slender and have a hook that protrudes from the anal fin.

Breeding Cardinal Tetras

Without a doubt, breeding cardinal tetras in home aquaria can be challenging at best.

Take note that you will need a separate breeding tank with stable water chemistry. This means using water with a pH ranging from 5 to 5.5 as well as softness of 3 to 4 dGH. What’s more, you ought to stock the breeding tank with fine-leaved plants since the cardinal tetras scatter their eggs on the surrounding vegetation.

In fact, most cardinal tetra females spawn in the evenings and can lay between 130 and 500 eggs. These eggs then take about twenty-four hours to hatch. Once hatching occurs, the young ones of the cardinal tetras live on yolk sacs for about four or five days.

After that period, the fry will be big enough to swim freely, so you can start feeding them with foods like egg yolk, rotifers, infusoria, or even commercially prepared fry food. It’s important to realize that the cardinal tetra fry are highly photosensitive and so the tank lighting should be dim.

Putting Cardinal Tetra and Neon Tetra Differences into Perspective

As illustrated above, neon tetras and cardinal tetras have many differences.

These include:

The Colouration

Neon tetras feature a luminous blue colouration in the upper portions of their bodies, while cardinal tetras have an upper vivid blue colouration.

Additionally, cardinal tetras are redder around their lower bodies than neon tetras.

The Size

In essence, cardinal tetras are slightly bigger than neon tetras because they can grow more by a total length of 1.25 inches.

Water Conditions

Although both cardinal tetras and neon tetras thrive in acidic water, their other tank water necessities aren’t similar.

Neon tetras work well with a pH of 6.2 to 6.8, while cardinal tetras survive best in a pH of 6.0 to 6.8. Additionally, cardinal tetras prefer water temperatures ranging from 75° to 85°, as compared to76° to 85° for neon tetras.

All in all, both of these species are quite popular and easy-to-keep. And you won’t go wrong by breeding any of them in your aquarium. Even so, ensure that you can meet each species’ specific requirements before you buy them.

Tetra Fish   Updated: August 1, 2019
avatar Hey, I'm Fabian, chief editor at Aquarium Nexus. I really enjoy the aquarium hobby and love sharing my experience with others. If you have any questions feel free to contact me or leave a comment below.

Leave a Comment

Your email address will not be published. Required fields are marked *