- Beta Gruis (β Gruis, abbreviated Beta Gru, β Gru), formally named Tiaki /tiˈɑːki/, is the second brightest star in the southern constellation of Grus. It was once considered the rear star in the tail of the constellation of the (Southern) Fish, Piscis Austrinus: it, with Alpha, Delta, Theta, Iota, and Lambda Gruis, belonged to Piscis Austrinus in medieval Arabic astronomy.