Please answer the following question: The black tetra (Gymnocorymbus ternetzi) also known as the black skirt tetra high-fin black skirt tetra and black widow tetra is a freshwater fish of the characin family (Characidae). It is native to the Paraguay and Guapore River basins of southern Brazil Argentina and Bolivia. Growing to about 6 cm (2.5 in) total length the black tetra has a roughly tetragonal body shape and is greyish in colour fading from near black at the tail to light at the nose. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
Answer:
Animal