The Cardinal Tetra is a delight for many aquarists, beginners and skilled alike. It is often mistaken as the Neon Tetra because of their likeness.
The difference between the two species is the Cardinal Tetra has a red strip all across its body, while the Neon Tetra will only display it halfway on the back half.
This species is very easy to take care of and can be kept with a lot of other peaceful fish, making a beautiful display of colors in your tank.
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Being a blackwater fish, the Cardinal Tetra will not do well in very brightly lit tanks. Keep the light dim and add dark colored substrate, as well as some pieces of driftwood and tangled roots to recreate their natural habitat. Some dry leaves may be added to color the water naturally with tannins released, but they need to be replaced every few weeks.
South American river basins do not feature a lot of plants, so there is no need for heavy planting. Instead, provide a lot of open swimming space, as Cardinal Tetras are very active and fast swimmers.
As for the water chemistry, they prefer very soft and acidic water with a pH between 4.5-7, and water temperature between 73-81 degrees Fahrenheit.
Feeding your Cardinal Tetra
The Cardinal Tetra mainly eats anything they can grab with their little mouth. In the wild, they are omnivorous, feeding on small crustaceans and worms, but in the home aquarium, they will accept regular flake food, live, or fresh foods.
Keep in mind they are in high need of vitamins, thus it is best to feed them mainly high-quality flake food.
If you plan on feeding your Cardinal Tetras twice a day, only give them what they can eat in about 5 minutes, but several feedings a day are always recommended. In this case, only give them the amount of food they would eat in 3 minutes.
If kept in a well-maintained tank with good quality water, the Cardinal Tetra will hardly become ill. But if water conditions become unstable, they are very likely to die off.
One particular disease affecting this species is the Neon Tetra disease, which was first diagnosed in Neons, hence their name. This is a very contagious disease of unknown cause, which is still incurable.
Though it is called Neon Tetra disease, it is known to affect other tetras as well.
They are very peaceful fish, which can get along with basically any other peaceful species. They do best when kept in very large schools, which makes them feel more secure.
They can, of course, thrive when being kept in smaller groups of up to 5 fish, but they may feel stressed out and probably pass away quickly.
The Cardinal Tetra is a schooling fish, which feels more at ease when kept in a school of at least 5, but a larger group would always be better. Keeping at least 10 or more of them together will also help boost their coloration.
Avoid larger fish that may think of your Cardinal Tetras as food, especially because they are so small. Even other larger Tetras may eat them if they could fit them in their mouth.
Try to keep them with other small and peaceful fish like other small tetras, Loricaiids, pencil fish, dwarf cichlids, or small rasboras.
Also, you can add more species variety in your tank by placing snails, shrimp, or crabs, which pose no threat to your Cardinal Tetras.
Breeding your Cardinal Tetra
Breeding can be quite tricky in the home tank and most fish are usually caught in the wild and shipped to the stores. If you still want to try to breed Cardinal Tetras, it is best to use a breeding tank and remove the pairs once the eggs have been laid to avoid eggs and young fry from being eaten.
Finding compatible pairs can also be a drawback, but can be achieved with a lot of patience.
The breeding tank must meet the same water conditions as those in their natural habitat, with optimal breeding temperature around 80 degrees Fahrenheit, but not lower than 75 degrees and a pH between 4.5-6.0, with very soft water and low lighting.
Cardinal Tetras, as well as the Neon Tetras, can make a sparkling addition to any tank, due to their bright coloration and very active behavior.
Remember to keep them in very large groups to make them feel more secure, while displaying the most vibrant colors.