Dottybacks (Pseudochromidae) are a diverse group of cryptic reef predators that are common on coral reefs throughout the Indo-Pacific and often display striking intraspecific color variation. In the Red Sea, this family exhibits high endemism, with some species displaying discrete color morphs. While at least one Indo-Pacific Pseudochromis species can switch between morphs in adulthood, it is unknown whether its Red Sea congeners share the capacity for color morph plasticity or whether balancing selection drives this variation. Using controlled aquaria experiments with environments simulating different reef states (live, bleached, and dead coral), we tested whether adult individuals of Pseudochromis flavivertex, which naturally occurs in four color morphs, two of them habitat-associated, can change color. The magnitude of color and pattern change were measured from standardized photographs and analyzed using a whole-color-pattern PCA. Across treatments, most individuals darkened over time, with morph-specific chromatic shifts: Morph 1 became redder, Morph 2 less yellow. Color and pattern analyses showed stronger and more consistent changes in Morph 1, but both morphs converged toward similar final morphologies. Habitat type did not significantly influence color or pattern trajectories, suggesting that other factors, such as reef-scale light conditions, diet, or interspecific interactions, may shape variation in the wild. This study provides the first evidence of adult color and pattern plasticity in P. flavivertex, underscoring its capacity for dynamic coloration and highlighting the complexity of color polymorphism and color change in reef fishes.