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Cardinal Tetra (Paracheirodon axelrodi)

Welcome to our detailed exploration of the Cardinal Tetra, a popular and vibrant fish that adds color and life to any aquarium. This article is crafted to provide you with all the information you need about Cardinal Tetras, from their distinct characteristics to their care requirements.

Cardinal Tetra Facts

Fact Category Description
Scientific Name Paracheirodon axelrodi
Common Name Cardinal Tetra
Native Habitat Orinoco and Negro Rivers in South America
Size Up to 2 inches (5 cm)
Lifespan 4-5 years
Coloring Vibrant blue and red stripes along the entire body
Temperament Peaceful and schooling fish
Water Conditions Soft, acidic water; Temperature 73°F – 81°F (23°C – 27°C)
Diet Omnivorous – prefers high-quality flake foods, small pellets, and live or frozen brine shrimp and bloodworms
Care Level Moderate
Aquarium Conditions Dark substrate, plants, and dim lighting to mimic natural habitat

Cardinal Tetra vs Neon Tetra

The Cardinal Tetra and Neon Tetra are both captivating, small freshwater fish popular among aquarists, but they have distinct differences. The Cardinal Tetra, known scientifically as Paracheirodon axelrodi, features vibrant blue and red stripes that extend the entire length of its body, creating a striking appearance. In contrast, the Neon Tetra (Paracheirodon innesi) has a similar color pattern, but its red stripe runs only halfway along its body.

Cardinal Tetras tend to be slightly larger, reaching up to 2 inches in length, compared to the Neon Tetra’s 1.5 inches. Lifespan also differs slightly, with Cardinal Tetras living up to 4-5 years, whereas Neon Tetras typically live for 8-10 years. Both species prefer similar water conditions and are known for their peaceful nature, making them excellent choices for community aquariums. However, their subtle differences in color and size can influence an aquarist’s preference for one over the other. Let’s compare these two beautiful fish:

Characteristic Cardinal Tetra Neon Tetra
Color Pattern Red and blue stripes run along the entire length of the body Red and blue stripes, but the red color only covers half the body
Size Up to 2 inches Up to 1.5 inches
Lifespan 4-5 years 8-10 years
Care Level Moderate Moderate

Cardinal Tetra Profile

The Cardinal Tetra (Paracheirodon axelrodi) is native to South America’s Orinoco and Negro Rivers. They are small, peaceful fish known for their striking blue and red colors and are a favorite among aquarium enthusiasts.

Cardinal Tetra Coloring

The Cardinal Tetra’s vibrant blue line that extends from its nose to tail, coupled with a lower red stripe, makes it a visually stunning species. This coloring not only adds aesthetic appeal to aquariums but also serves as camouflage in the wild.

Cardinal Tetra Habitat

Cardinal Tetras originate from the slow-moving, acidic waters of the Amazon basin’s tributaries, specifically the Orinoco and Negro Rivers. These densely vegetated areas provide a dark, serene environment ideal for these brightly colored, peaceful schooling fish.

Cardinal Tetra Aquarium Setup

Creating the ideal aquarium environment for Cardinal Tetra fish is crucial for their health and well-being. This section will guide you through setting up an aquarium that mimics their natural habitat.

  • Tank Size

Begin with a tank of at least 20 gallons to provide ample space for a school of Cardinal Tetras. These fish thrive in groups, so a larger tank allows for adequate swimming space and helps maintain a stable water environment.

  • Water Conditions

Cardinal Tetras prefer soft, acidic water with a pH between 4.5 and 6.5. The ideal temperature range is 73°F to 81°F (23°C to 27°C). Regular water changes and a good filtration system are essential to keep the water clean and at the right parameters.

  • Substrate and Decor

Opt for a dark substrate to replicate the riverbeds of their natural habitat. This not only makes the fish more comfortable but also enhances their vibrant colors. Decorate the tank with driftwood, rocks, and a variety of live plants like Java Fern and Anubias, which can tolerate low-light conditions.

  • Lighting and Filtration

Dim lighting is preferred as it closely resembles the shaded areas of their native rivers. A reliable filtration system is vital to maintain water clarity and remove toxins, but ensure that the water flow is not too strong to avoid stressing the fish.

  • Schooling and Compatibility

Cardinal Tetras are schooling fish and should be kept in groups of at least six. This not only makes them feel secure but also encourages natural behavior. They are peaceful and can be housed with other similar-sized, non-aggressive fish.

Cardinal Tetra Fish Breeding

Breeding Cardinal Tetras can be a rewarding experience for aquarists. This section will cover the specifics of creating a conducive breeding environment and the spawning process.

Breeding Environment Setup

To encourage breeding, set up a separate breeding tank. This tank should be around 10-15 gallons and have soft, acidic water with a pH of around 5.0-6.0. The temperature should be slightly higher than in the main tank, ideally around 80°F (27°C). Use a sponge filter for gentle filtration and include fine-leaved plants or a spawning mop to give the fish a place to lay their eggs.

Conditioning the Breeding Pair

Before breeding, condition the breeding pair with high-quality foods like live brine shrimp, daphnia, or bloodworms. This increases their health and vitality, improving the chances of successful spawning.

Spawning Process

Cardinal Tetra fish usually spawn in the early morning. During spawning, the female lays dozens of eggs, which are then fertilized by the male. These eggs are adhesive and will stick to the plants or spawning mop. After spawning, it’s advisable to remove the adult fish to prevent them from eating the eggs.

Egg Care and Fry Development

The eggs will hatch in about 24 hours. The fry are initially very small and can be fed infusoria or commercially available fry food. As they grow, you can gradually introduce them to larger foods like baby brine shrimp. Consistent water quality is crucial during this stage, and regular, gentle water changes are recommended.

Cardinal Tetra Diet & Feeding

Cardinal Tetras are omnivores. In the aquarium, they should be fed a variety of foods, including high-quality flake food, small pellets, and frozen or live brine shrimp and bloodworms. Regular, small feedings are preferable.

Cardinal Tetra Compatibility

These peaceful fish do well in community tanks with other small, peaceful species. Avoid pairing them with large or aggressive fish that might view them as prey. Ideal tankmates include neon tetra, glass fish, barbs, discus, pencilfish, rasboras, dwarf gourami, honey gourami, black phantom tetra, catfish and ram cichlid.

Cardinal Tetra Common Diseases

Cardinal Tetras are susceptible to common freshwater fish diseases such as Ichthyophthirius (Ich), fungal infections, and fin rot. Preventing these diseases involves maintaining clean water conditions, avoiding overfeeding, and ensuring a stress-free environment. Early detection and treatment are crucial for the health of these delicate fish.


Wrapping up, the Cardinal Tetra is a beautiful, peaceful fish that can make a wonderful addition to many aquariums. It is often confused with its cousin neon tetra but there are many differences between the two. With proper care and a suitable environment, Cardinal tetra fish can thrive and bring vibrant color and activity to your aquatic setup.