Tetras are a fabulous family of tropical fish species, arguably the most kept species of tropical fish in the aquarium hobby. They are generally very hardy and come in many different varieties of colours, from the somewhat drab Black Widow Tetra to the iridescent red & blue Cardinal Tetra. They are renowned for having a peaceful nature, except for a few, such as the Bucktooth Tetra, making them a must-have addition to many aquarium setups.
Below is a list of 155 different types of Tetra (with photos) found in the fishkeeping hobby, both rare and common.
Tetra is the commonly known name for many small freshwater characiform fish belonging to the biological family Characidae and the former subfamilies Lebiasinidae and Alestidae. There are currently over 800 types of tetra fish species distributed among these three families. Characidae can be recognised from other fish by their small adipose fin located between the dorsal fin and the tail. This adipose fin serves as the fourth unpaired fin on these fish. Although this adipose fin is often considered a distinguishing feature, some Tetras, such as the Emperor Tetra, lack this characteristic.
Many of these fish possess several bones that connect the swim bladder to the inner ear, enhancing their hearing capabilities. A majority of these colourful tetra fish are also brightly coloured and relatively easy to care for in captivity. As a result, they are extremely popular in home aquariums as tetra aquarium fish.
Tetras generally have compressed bodies and are typically identified by their fins. They often possess a tall dorsal fin and a homocercal caudal fin, which is joined to the body via a short connection. Additionally, many Tetras have a long anal fin that extends from behind the dorsal fin and ends near the ventral caudal peduncle. Some species also have a small, fleshy adipose fin between the caudal and dorsal fins.
Species such as the Cardinal Tetra and Neon Tetra are among the most popular tetra fish, adding vibrant colour and social interaction to community aquariums. Tetras range in size from 4 cm to 15 cm, though most small tetra fish species available to aquarists are smaller. With proper care, tetras can live for 5 to 10 years.
Natural Habitat
Tetras are native to South and Central America and Africa, with many species originating in the Amazon Basin. However, the Blind Cave Tetra is an exception, having been discovered in Mexican cave systems.
Tetras inhabit a variety of regions, ranging from expansive areas to single river systems. Each tetra species has a specific distribution and range, although some populations overlap.
Many live in areas with submerged vegetation and shaded regions, making them ideal tetra aquarium fish.
Behaviour
Most tetras are colourful, peaceful, and calm, making them ideal for community aquariums with similarly sized fish. However, some exceptions exist. For instance, Serpae Tetras can be prone to fin-nipping, especially if kept in insufficient numbers. Meanwhile, species like the Buenos Aires Tetra can grow relatively large and exhibit high activity levels, which may intimidate smaller or more timid tank mates.
In the Aquarium
In the wild, tetras are typically found in soft, acidic water. However, most aquarium species sold today are commercially bred in environments with a higher pH and alkalinity than their natural habitats. For most tetras, the recommended water temperature is between 24°C and 27°C, with a pH of 6.8 to 7.8 and alkalinity within the same range.
If your aquarium room temperature is below 24°C, using an aquarium heater is advised. Exceptions, such as the Buenos Aires Tetra, can thrive in cooler water. Maintaining good filtration, a steady water current, and regular water changes is essential. Be sure to use a dechlorinator if you are using tap water.
Tetras can be housed in aquariums ranging from 35 to 90 litres, although larger tanks are easier to maintain and provide more swimming space. They thrive in schools of six or more, reducing stress and encouraging vibrant colouration. Aquariums with dark substrates and dense decorations can enhance their appearance. Always use a securely fitted lid, as tetras may jump if startled.
Suitable tank mates for tetras include other tetra fish species, Danios, Rasboras, appropriately sized Rainbowfish, smaller peaceful Barbs, and Livebearers.
Feeding
Most tetras are omnivores and thrive on a varied diet of high-quality dried foods such as flakes, granules, wafers, and pellets. Occasional feeding of frozen or live foods is beneficial, especially when encouraging spawning. A diverse diet will yield the best results.
Feed your tetras once or twice daily, offering only as much as they can consume in under two minutes.
Breeding
In the wild, tetras normally breed during the rainy season. In aquariums, controlled conditions enable year-round breeding. Female tetras typically become reproductive at 9–12 months of age, though larger species may not mature until 1.5–2 years.
To prepare for breeding, house males and females in the same tank but separated by a partition for 2–3 weeks. When ready, move the female to a breeding tank with live plants and established water conditions the night before, then introduce the male the next day.
Monitor the male's behaviour carefully, as aggression may occur. If necessary, remove the female and reintroduce her later. Including multiple females can reduce the male's focus on a single individual. Breeding is most successful in dimly lit environments with minimal visibility.
Once eggs are fertilised, remove the male immediately to prevent predation on the eggs or female. The eggs hatch within 24 hours, and the fry should be fed infusoria initially, followed by baby brine shrimp and commercial fry food as they grow.
By understanding the care requirements and behaviour of different types of tetras, aquarists can create thriving, vibrant aquariums. Whether you are a beginner or experienced, these colourful tetra fish make an excellent addition to any tank.
