One of the most popular fish for the home aquarium has got to be the Cardinal Tetra. One look at a planted aquarium with a tight shoal of these absolute beauties can hook anyone into wanting to start a fish tank.
The Cardinal Tetra (Paracheirodon Axelrodi) is found naturally in South America in the upper Orinoco and Negro rivers. These rivers have a completely different water chemistry to most peoples mains tap water and subsequently their aquariums. They are naturally more acidic and have a lower mineral content and are often referred to as "black water rivers". Its this huge difference in water quality which can lead to problems. It is important to ask what water parameters the fish you are looking at are kept in. Some shops stock wild farmed specimens, these need to have very specific water conditions to thrive. Most places now sell fish that are raised in much harder more Alkaline water so used to the kind of conditions in the majority of home aquariums.
Ideally they would be kept in softer more acidic water (you can buy various buffers and additives to achieve this) and if you wanted to breed them this is essential. Cardinals are very difficult to breed in the home aquarium, you need very large numbers and an even bigger swimming area as their natural habitat needs to be mimicked closely.
I would always recommend Cardinals are introduced to mature and stable systems, they do not agree with water quality fluctuations so a mature system will limit this.
Cardinal Tetras are a shoaling fish so the more you have the better - at least 4 but i would recommend 12 or more. They love a well planted tank with tall plants to create shaded areas. Try and avoid bright lighting if possible. Having floating plants will create shaded areas and provide a sense of security for your fish. I think it looks amazing when fish swim from light to dark areas. They will accept a variety of foods including flakes and small pellets but really benefit from live or frozen daphnia, it really keeps the colours bright and vibrant. They are a peaceful community fish and get along with pretty much everything. Avoid anything to large as Cardinals are a nice bite size to large predatory fish. They are a relatively long lived fish and can have a life span of up to 5 years if cared for properly.
Cardinals really are a stunning addition to any community aquarium, and look even more dramatic in a species only display.
It's easy to see why they are amongst the top, if not the most popular fish for a home aquarium.
