Pinktail Triggerfish

The pinktail triggerfish has an oval body and may grow up to 40 cm (16 in) in length, and is not sexually dimorphic. Like all triggerfish species, the first dorsal fin is composed of three spines that can be “triggered” up and down (to lock the fish inside crevices to thwart predators when necessary), and the anal and second dorsal fins, undulating left and right, serve as the primary method of locomotion. The caudal fin, notably pink, can be splayed from a squared to a wide rounded, almost truncated shape for different burst movement options. The pectoral fins are rather unremarkable (apart from being bright green), and the pelvic fins are nearly invisible, being quietly tucked underneath the ventral side. The pinktail triggerfish has a small terminal mouth, as well as small eyes, and the body is covered in tough cycloid scales.

The pinktail triggerfish is found throughout the Indian and Pacific Oceans. The greatest population density occurs around Indonesia and Oceania, but this fish can be found as far west as East Africa, as far east as the western coast of Panama, and as far north as southern Japan.

The pinktail triggerfish lives exclusively in shallow coral reefs, preferring reef slope edges near the surface. This is likely due to its planktivore diet, where currents from more open ocean can provide a constant supply of plankton. Adults prefer areas with large corals, while juveniles prefer rockier parts of the reef, as they provide better cover against predators.

The pinktail triggerfish is a planktivore, feeding on microalgae especially. This is somewhat unique among triggerfish, as a majority of species consume hard-shelled invertebrates like crabs and urchins with their crushing teeth. The pinktail triggerfish is also ovivorous, and is known to follow spawning fish individually and in pairs to consume the eggs. Species whose eggs are prone to predation by the pinktail triggerfish come from a wide range of orders, and include Aulostomus chinensis, Parupeneus bifasciatum, Chlorurus sordidus, Acanthurus nigroris, Bothus mancus and Ostracion meleagris. The preference for these fish species was determined to be due to the fact that they spawn in pairs, which correlates with larger egg sizes.

The pinktail triggerfish is listed as a Least Concern species by the International Union for Conservation (IUCN) due to the large population, widespread range, and relative indifference from humans (due to its inedibility: it contains ciguatoxins and palytoxin, both of which originate from its microalgae diet). There are, however, a few threats that could perhaps change this listing, for example the continued death of corals and degradation of coral reefs due to climate change and ocean acidification, which can result in habitat loss.

The pinktail triggerfish can be found in the aquarium trade, and all individuals are wild-caught. However, so far there is only one fishery in Micronesia that harvests them, and it is reported that it follows sustainable fishing practices.