Longnose Filefish

As its common name suggests, this fish has bright orange spots all over its blueish, greenish skin. Even their eyes have some orange lines present. Their tail is pale with a distinguishing black spot; however, the black spot disappears when the caudal fin flares out. Instead of paired pelvic fins, it has a pelvic flap that is bordered in black and has white spots, reduced pelvic rays, and a lack of pelvic spines. It has an elongated dorsal and anal fin, and its pectoral fins are very reduced. Their large anal and dorsal fin aids in locomotion through coordinated undulation or oscillation. The snout of O. longirostris is elongated and has a small mouth opening at the tip. Their teeth are fused and form a hooked beak structure with a tooth flanking on either side. Male and female O. longirostris are about the same size, typically ranging in length from 42mm to 75mm. They also show slight sexual dimorphism as males are a slightly darker blue-green color and their pelvic flap has a bright orange ornamented area, while the female's ornamented area in their pelvic flap is a duller orange color and a lot smaller or even lacking.

Orange spotted filefish can be found in the Indo-Pacific, on shallow coral reefs. Two of the main things that account for the distribution of this species of fish are the availability of branching coral and coral richness. Meaning that habitats with structural complexity and preferred prey availability, such as Acropora, are key factors for habitat selection.