Cardinal Tetra vs Neon Tetra: Which One is The Crown Jewel of Your Aquarium?


One of the most popular fish that you can find in almost all aquariums is the tetra fish. They grab your attention with their dazzling color markings. Distinguishing between Cardinal Tetra vs Neon Tetra can be confusing for beginners. The cardinals are a bit larger than neon and have slight variations in their markings. You can distinguish the neon tetra by its slightly transparent body.

Suppose you are looking to have either of these tetra fish these crown jewels in your aquarium. In that case, this guide will help you understand these magnificent species.


Neon Tetra
Neon Tetra

At first glance, you will not find much difference between these two species. They have many similar characteristics. But if you have a keen eye for them, you will find many differences. 

Both species have their origin in the South American continent. They are predominantly found in the clear waters of the Amazon river’s tributaries widely distributed in river streams of Brazil, Peru, and Columbia. Because of their brilliant color markings, they became a trendy aquatic pet.

Most of the captive tetras in the floating market are not wild and are the result of breeding. The Neon Tetra and Cardinal Tetra are social animals. They live in large groups known as schools. Hence it would be best if you housed at least half a dozen of them in your aquarium.

These two fishes have a brilliant neon blue color stripe that runs throughout the length of their body. Below the blue stripe, there is a vivid red stripe in both the fishes. The red stripe in neon is present from the middle of the belly and extends to the tip caudal fin. In cardinal tetra, the red stripe extends the full length of the fish.

Another distinguishing feature between these two is that the cardinal tetra is larger than the neon tetra. The red stripe will fade away in both fishes when they are resting or ill. It would help if you did not choose a tetra that does not have rich coloration. It can be an indication that the fish is sick. 

Aquatic Conditions

Cardinal Tetra
Cardinal Tetra

The natural habitat Neon tetra and Cardinal tetra consists of brackish water with high vegetation. They prefer darker places and tend to live under shades of aquatic vegetation. 

The minimum tank capacity for neon tetra is 10 gallons and 20 gallons for the cardinal.

The water must be soft and acidic, with a pH of less than 7. These two species will not tolerate the change in their habitat. Hence, before you introduce them to the aquarium, make sure you condition it properly.

The general water hardness (dGH) should not be more than 10 for neon tetras, whereas, for cardinal tetras, it should be 4. Live plants provide excellent hiding and natural habitat conditions for the tetras. Provide live submerged plants as well as floating leaves. 

The ideal temperature for both of them should be between 23 to 27 degrees Celsius. Please provide as many dark hiding spots as possible, but it does not mean that you should make the tank fully dark. The water should be acidic and soft. You can use driftwood along with plenty of natural plants to mimic their natural habitat.

Tank Mates

You can house both tetras together. They will get along with each other because the size difference between both is not significant. You can house smaller fishes such as other smaller tetras, rasbora, guppies etc.

Larger and popular aquarium pets such as cichlids, angelfish, catfish, and larger goldfish will eat the tetras whenever given a chance. It is better to avoid this combination. Do not house larger or aggressive tetras. They will prey on smaller tetras whenever they get a chance.House fishes that are similar in size to tetras. 


Both tetras are omnivores, and you can feed both plant and animal food. They have high protein requirements, so make sure you feed them with quality food. They love to eat live or frozen food but do not feed them often because they can develop rejection.

Feed them multiple times a day. Give them small pieces or flakes of food since these species have small mouths. Mix the types of food you feed them, such as prepared food, live, and frozen food.


Sexual dimorphism in both species is not distinguishable. In both species, both sexes show similar colors. The only difference is females are a bit larger than the males but not overly broad. It is their bellies that are large in females than males.

The blue stripe of neon tetras will appear curved in females because of their bellies, whereas it is straight in males.

The breeding requirements are precise for tetras. If you want to breed them, you need to house them in separate tanks, provide ideal water conditions, and live plants. The ideal tank conditions for breeding will slightly differ from the normal.

The water conditions for breeding:

  • Neon Tetra: pH – 5 to 6 and dGH 1 to 2
  • Cardinal Tetra: pH – 5 to 6 and dGH 3 to 5

The optimum temperature of 24 degrees Celsius is suitable for both species. Gradually increase the intensity of the light, which will induce the female to spawn eggs. The fertilization is external in both tetras. Once the eggs are released, separate the parents as they tend to eat them.

The eggs have an adhesive layer that helps them to stick to the surface of the live plants. Reduce the intensity of the light as the eggs and young fry are sensitive to it.

The eggs will hatch in 24 hours, and the fry will be free-swimming within a week. You can use some floating plants or leaves to make the tank a bit shady.

The fry of both tetras will attain sexual maturity and exhibit their brilliant colors in one month.

Which one is the Best Tetra for You?

Both the tetras are suitable for housed together are in separate tanks. They are highly social, and you must house at least half a dozen each. If you condition the aquarium properly and provide ideal conditions that mimic their natural habitat, they will do well.

Before you buy a tetra, observe the color and other physical characteristics such as the fins’ shape and behaviour. A restless and pale tetra indicates it is not a healthy one. Please do not buy these as they can infect other healthy tetras.

If you have chosen between cardinal tetra vs neon tetra, let us know. We would love to hear your story.

Archiwum: listopad 2020

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