Scylla

Scylla is a Secret fish which can be caught in the Veil of the Forsaken, which is the fifth and final area in Mariana's Veil, after defeating the Scylla Boss. When reeling it in, -95% Progress Speed is applied. The catch rate is 0.32% (1/313), with Aurora Borealis the catch rate is 1.92% (1/52).