Ornate Butterflyfish

Chaetodon ornatissimus is most easily identified by its color pattern, which helps protect it from predators. Ornate butterflyfish have white bodies with orange to orange-brown oblique bands. They also have two yellow-edged black bars on their head: one runs across the eyes and the other is on the snout, and the tail has two black bars. The size of the ornate butterflyfish ranges from 13 to 18 cm total length (mean ± SD = 16.2 ± 1.4 cm) and pair members are nearly always indistinguishable based on size.

The ornate butterflyfish is widespread throughout the tropical waters of the Indo-Pacific area, ranging from Sri Lanka to Hawaii, the Marquesas, the Pitcairn Islands, North to Southern Japan, South to Lord Howe, and Rapa in the Austral Islands. Over three-quarters of the world's fish species inhabit this region. The environment C. ornatissimus lives in is marine, inshore, tropical (30°N – 30°S, 77°E – 124°W) and reef associated. They tend to live at a depth range between 1–36 meters.

Ornate butterflyfish feed exclusively on coral polyp tissue and small organisms. Ornate butterflyfish feed on ten different coral species, which is the broadest range of corals when compared with other coral-eating butterflyfish species. Other obligate corallivores (coral-eating) butterflyfish species include: Chaetodon austriacus, C. baronessa, C. bennetti, C. larvatus, C. lunulatus, C. meyeri, C. octofasiatus, C. rainfordi, and C. trifasicatus. Butterflyfish are obligate corallivores, which means the majority of their diet must be made up of live coral polyp – coral mucous rather than coral tissue. Butterflyfish have very fine hair-like teeth that enable them to pick out small organisms inaccessible to most other fish for eating. They thrive mainly on a diet of coral polyps, tentacles of feather dusters and Christmas-tree worms.

Ornate butterflyfish adults are predominately found in pairs that occupy exclusive territories, including Clearwater lagoons and seaward reefs rich in coral growth (size range ~100–1400 m2). On the other hand, juvenile Chaetodon ornatissimus live in solitary, tend to be shy, and hide in the arms of branching corals for protection. Once juveniles reach breeding age, they form pairs. It is uncommon to find adult Chaetodon ornatissimus without a mate. Pairs also establish a "home range" where they are likely always to be found.

Ornate butterflyfish are monogamous and pair-forming coral reef fish. Many ornate butterflyfish mate for life. Spawning activity occurs at different times depending on each biome. Tropical spawning peaks in winter and early spring, while temperate spawning occurs in midsummer. Spawning occurs at dusk and eggs are released and fertilized in the water column.

Ornate butterflyfish like other coral reef organisms, have many natural and anthropogenic disruptions which play a major role in loss of habitat of. Sessile, benthic communities on tropical coral reefs experience natural disruptions including tropical storms, unseasonal temperature extremes and infestations of crown-of-thorn sea stars (Acanthaster planci). These events are becoming more frequent, which makes anthropogenic influences more chronic. Anthropogenic disturbances include overfishing, pollution and coastal development, all of which cause depletion in corals. Over 30 percent of the coral reef communities in the world have already been degraded; however, by 2030 more than 60 percent of coral reef communities will have been lost.