Characins, commonly known as tetras, belong to one of the most species-rich groups of freshwater fish. They are foundational to the aquarium hobby, recognized by most for their lively schooling behavior and vibrant colors.
Characteristics and Taxonomy
One of the most distinctive features of most characins is the presence of a small adipose fin located between the dorsal and caudal fins. Scientifically, most of our popular aquarium species in this group belong to the family Characidae. They are found naturally in South and Central America as well as Africa, providing aquarists with ample opportunity to create authentic biotope aquariums.
Natural Habitats and Water Parameters
South American species, such as the famous Cardinal Tetra (*Paracheirodon axelrodi*), often inhabit soft and acidic blackwater (pH 5.0-6.5). Many of these areas are characterized by fallen leaves and driftwood that release tannins into the water. To bring out the best colors in your tetras, it is recommended to use a dark substrate and dimmed lighting, as this makes their iridescent colors pop.
Behavior and Social Life
Characins are quintessential schooling fish and should never be kept alone. A group of at least 10 individuals is necessary for them to feel secure. In a larger school, you will witness their natural interactions, and they will feel less stressed. They are generally peaceful and ideal for community tanks, though one should note that certain larger species can be predatory toward very small tank mates.
Diet and Breeding
As omnivores, they are very easy to feed. They thrive on a varied diet of flake food, pellets, and small frozen foods like cyclops and brine shrimp. Most tetras are egg scatterers that exhibit no parental care. In nature, they often spawn in dense vegetation, and in the aquarium, successful breeding typically requires very soft water and specific conditions.