Disk tetra

Care at a glance

Overview

Keep disk tetras in a group, as they school for security, and plan on a huge tank of around 645 liters given their adult size. They are peaceful, active swimmers that hold the middle and upper water. Target the mid 20s C and a soft, acidic to neutral pH. Feed a plant-heavy diet with vegetables and prepared foods, plus some protein from insects or small crustaceans.

In the wild

Disk tetras live in rivers and seasonal floodplains of the Amazon and Orinoco basins across Venezuela, Peru, and Brazil. They use clear and blackwater stretches with moderate to strong current, around submerged wood and plants. The water is soft and slightly acidic. At home this means a very large tank with steady flow, open swimming space, and robust plants or decor that can take some grazing.

Good to know

This is a member of the Serrasalmidae family, the same broad group as pacus and piranhas, though it is a plant-leaning omnivore. It is a big fish, reaching around 40 cm, with a tall disc-shaped body, silver sides, and a bold black bar. It has teeth suited to cutting plant material, and there is no real home breeding record for it.

Did you know

It eats a lot of fruit and seeds in the wild and passes many of those seeds intact, so it helps spread riverbank plants as the floodwaters move it around. That makes a big plant-eating fish part of how the forest along the river regrows.

Related species

• Black piranha

  Serrasalmus rhombeus

  15.7 in (40 cm)106 gal (400 L)75–82°F (24–28°C)

• 

  Redhook

  Myloplus rubripinnis

  9.8 in (25 cm)70 gal (265 L)73–81°F (23–27°C)

• 

  Red-bellied Piranha

  Pygocentrus nattereri

  12.6 in (32 cm)160 gal (605 L)75–82°F (24–28°C)
• Spotted metynnis

  Metynnis maculatus

  7.1 in (18 cm)92 gal (350 L)73–82°F (23–28°C)

• 

  Spotted silver dollar

  Metynnis lippincottianus

  5.5 in (14 cm)53 gal (200 L)73–81°F (23–27°C)

• 

  Red-bellied pacu

  Piaractus brachypomus

  34.6 in (88 cm)1,057 gal (4,000 L)73–82°F (23–28°C)