Green Scat

Scatophagus argus was first formally described in 1766 as Chaetodon argus by Carl Linnaeus with the type locality given as India. In 1831 Georges Cuvier described the genus Scatophagus and Linnaeus's C. argus was designated as its type species. The specific name argus refers to the mythical hundred-eyed guardian of Io, Argus, who following his death had his eyes became the feathers of a peacock, a reference to the brown to reddish-brown spots on the body of this fish.

Scatophagus argus has a wide Indo-Pacific range. It is found from the Persian Gulf, along the south Asian coast into the western Pacific. It occurs as far north as Japan south to New South Wales, New Caledonia, and Fiji. It has also been recorded from French Polynesia. This is a species of sheltered, shallow coastal waters such as estuaries, harbours, mangrove pools, and the lower parts of fresh water streams, particularly where there are high mineral concentrations. The very small juveniles float within the surface film of the water.

Scatophagus argus is omnivorous and an indiscriminate eater. In 1992, biologists Barry and Fast reported adult scat from the Philippines were primarily herbivorous, while the juveniles preferred zooplankton. This species forms schools. The females attain sexual maturity at around 7–9 months of age and when the weigh , whereas the males are sexually mature at a smaller size. In the Philippines, spawning is brought on by the monsoon rains that start in June and July and the increased rainfall brings cooler temperatures, increased river outflows and lower salinities. The eggs are about in diameter, they are transparent and have a spherical shape. The larvae take around 20 hours to hatch from fertilisation and on hatching are in length. The juveniles pass through a pelagic tholichthys larval stage, like butterflyfishes.

Scatophagus argus is fished for and eaten by some people from its original environment, and can sting with small spikes in its anterior parts, inflicting a venom that causes great pain and dizziness. Treatment of the wound is often done by soaking the site of invenomation in hot water. It also appears in the aquarium trade.

n worm Pararhadinorhynchus magnus]] Scatophagus argus harbors parasites, like most fish. The acanthocephalan worm Pararhadinorhynchus magnus has been described from the intestine of this fish in waters off Vietnam.