Select options Costae Tetra (Moenkhausia costae) $22.99 – $179.99 A rarely seen and highly sought-after species of schooling tetra, the Costae or Blackline Tetra is found in the shallow reaches of the Rio Sao Francisco and its tributaries in Southern Brazil. An extremely active species, they form large schools or shoals in the wild as a defense from predation. In the aquarium, their fast-moving nature and unique tail stripe pattern adds flash and movement to the middle and upper levels of the aquarium which has made them extremely popular with planted tank hobbyists and aquascapers. A hardy species, they are tolerant of a wide range of water conditions but should be kept in a well-covered aquarium as they are likely to jump. As a shoaling species, they should be kept in larger groups, with 5 fish being the minimum (more fish are better if space allows).