The Formosa Wrasse (Allocoris formosa) is a heavy-bodied Western Indian Ocean wrasse known for dramatic color change as it ages and changes sex. Juveniles are orange to deep red with broad white bars edged in black and black markings in the fins. Females shift to gray-green or dark blue-green with black spotting, reddish fins, and blue lines across the face, while terminal males take on reddish, lavender, brown, or pale blue tones with contrasting vertical markings and spotted fins. The species ranges from the southern Red Sea and eastern Africa south to South Africa and east to Sri Lanka, where it occupies rocky, weedy, and coral-covered terrain; juveniles turn up in shallow tide pools. Adults commonly reach about 20 inches, with documented individuals approaching 24 inches.

Housing must be built around that adult size. A 220-gallon aquarium is the practical minimum, arranged with broad open swimming lanes and rocky crevices the wrasse can patrol and hunt through. A 4- to 6-inch bed of fine to medium-fine sand is essential, since this fish buries itself at night and whenever it feels threatened. Secure all rockwork on the bottom glass or a solid base; adults dig vigorously, overturn loose material, and will rearrange an unanchored aquascape. A tight-fitting lid is necessary because the species jumps, and filtration should be sized generously for a large, active predator with a substantial feeding and waste load. An established system is the right starting point rather than a newly cycled one.

Given the digging, the appetite for invertebrates, and the eventual bulk of a mature specimen, a large fish-only-with-live-rock system is the setting where this wrasse performs best over the long term. Care is moderate rather than beginner-friendly, driven less by water chemistry sensitivity than by the scale of the enclosure and the careful tankmate selection the species demands.