By Rajiv Sharma*

Serpae tetras are popular schooling fishes. These are also known as Callistus tetras or Blood tetras. They are very beautiful flame-coloured slow-moving fishes. They are easy to care for and are robust; many aquarists keep them in community and planted aquariums around the globe.


Serpae tetras’ body is small, flame to bright red coloured. Their dorsal fin is black with white spots. The anal fin is also black with white patches on fins. Females are fat and bigger in size in comparison to males; their colour is also faded. Males are smaller in size and brighter in colour. They belong to Characidae family.

The can live upto 4–5 years in aquariums. Serpae tetras exist in two variants i.e. short- and long-finned Serpae tetras. Long-finned Serpae tetras are more attractive and slow movers in comparison to short-finned Serpaes. They should be kept in a school of more than 6 fishes. They show their true colour and behaviour in planted aquariums. Their vibrant red-flame-coloured elongated laterally compressed oval-shaped body adds colours in planted aquariums.

Feeding Habits and Behaviour

Serpae tetras are omnivores and easily accept flake foods and pellet foods in aquarium like other tetras. In nature, they depend on insects, fishes, and vegetation. Their mouth is small, so offer only small sized flake or frozen foods. Proper feeds improve colouration of Serpae tetras. They happily accept lettuce, flake foods, dry worms, frozen worms, and blood worms in home aquariums.

They are peaceful fishes and can live happily with other same size fishes. They are also known as fin nipping fishes. Serpae tetras can nip the fins of same species at feeding time. They can also nip fins of other fishes having long fins, so it is not advisable to keep them with long-finned fishes such as bettas and angel fish. Sarpae tetras can also harass slow-moving fishes. They are peaceful but can also show aggression towards small tank mates. 

Water Quality

Serpae tetras originally belong to backwaters of Paraguay and South America. They live in densely vegetated and slow-moving rivers, lakes, and ponds. The water of these water bodies is calm, murky, soft, and slightly acidic with lots of vegetation. In home aquariums, aquarists should try replicate their natural habitat by adding a variety of aquatic plants and providing a lot of swimming area and acidic water. The temperature range should stay between 24 and 27 degree Celsius.

Tank Setup

A two feet aquarium is suitable to house a school of 6 Serpae tetras. They like acidic murky water. Adding some driftwood in aquarium is helpful for making water acidic. It is advisable not to keep them with aggressive fishes: It is best to keep them only with peaceful fishes. Any large sized fish can harass and eat them. Some important points to keep in mind when setting up a Serpae tetra aquarium are as follows:

  1. Dark or gray coloured substrate or sand helps in replicating murky environment.
  2. Water should be soft and acidic. It is advisable to use RO water.
  3. Plenty of driftwood mimics the black water habitat. Woods also work as natural water conditioner.
  4. Plants are considered very important for Serpae tetra aquarium. They provide natural shelter and food to fishes. The latter also lay eggs over plant leaves. Arrange plants in bunches along with aquarium walls. Middle area should remain open to provide them space for swimming.
  5. Water circulation should be moderate to slow. They don’t like high water circulation.
  6. Amazon water bodies don’t allow too much light to reach into water, so keep subdued lights for an ideal Serpae tetra aquarium. Some floating plants may help in reducing light.
  7. They can be kept in a community aquarium with other small sized fishes such as tetras, danios etc. Keeping Serpae tetras with big sized, long-finned fishes is not advisable.

Taking Care of Serpae Tetras

Keeping Serpae tetras is not a rocket science. They are easy to keep and maintain. They don’t have any specific requirements. Following are some important points that should be kept in mind in order to maintain a Serpae tetra aquarium:

  1. Water should be clean with slow to moderate circulation. Clean its filter from time to time. Serpae tetras can live happily in a wide range of water parameters. Water should be chlorine free.
  2. Keep them with dark substrate to enjoy their vibrant red colour contrast.
  3. Most of the living creatures like greenery. They belong to water bodies full of vegetation, so keep them in planted aquarium with a lot of space available for swimming.
  4. Never keep them with territorial and aggressive fishes.
  5. Introduce them in a properly cycled aquarium. Slightly acidic water and subdued light will be beneficial for them.

Happy Fishkeeping!

* The author is founder of online aquarium forum, an aquarium hobbyist and planted aquarium designer. email id:, Ph. 9958075234