Black Widow Tetra (Gymnocorymbus ternetzi)
Also known as Black Tetra or Black-skirt Tetra, the Black Widow Tetra is a hardy, lively character, who can be nippy with smaller fish, so is best housed in a community aquarium with peaceful larger species. They are less likely to fin-nip if kept in a larger group of their own species (they will be preoccupied with each other rather than bothering other tank-mates). They are found wild in Paraguay and nearby, in South America, mostly in small, slow moving rivers, streams, and tributaries that are well shaded. They sometimes breed in a home aquarium, and will scatter eggs among plants and undergrowth. They are very tolerant of a range of water parameters and will eat anything, making them a perfect beginners’ fish.
Size (fully grown): 5.5cm (2.2″)
Water temperature: 21 – 26C
Water pH: 5.8 – 8.5