Spotted scat
A spotted, square-bodied fish from Indo-Pacific estuaries.
The spotted scat is a hardy, omnivorous fish found in shallow coastal waters across the Indo-Pacific. It adapts to varying salinity levels and is popular in the aquarium trade, though its spines carry a painful venom.
- Grows up to 38 cm in length.
- Venomous spines cause pain and dizziness.
- Adapts from freshwater to saltwater environments.
- Popular in the home aquarium trade.
- Spawning triggered by monsoon rains.
What it is
This fish has a rectangular, strongly compressed body with a steep head profile. Its colour ranges from greenish-brown to silvery, covered in brown or reddish spots. Juveniles may show dark vertical bars instead. The dorsal fin contains spines separated by a deep notch, and the mouth is small and horizontal. Small ctenoid scales cover the skin. Two main colour morphs exist, known as green scat and ruby scat.
Where it lives
The species inhabits the Indo-Pacific region, extending from the Persian Gulf to Japan, New Guinea, and southeastern Australia. It also occurs in New Caledonia, Fiji, and French Polynesia. A small population likely established itself in the Mediterranean near Malta after 2007. These fish prefer sheltered, shallow areas like harbours, mangrove pools, and estuaries with high mineral content.
How it lives
Spotted scats are omnivorous and indiscriminate eaters. Adults tend to be herbivorous, while juveniles feed on zooplankton. Despite the genus name meaning dung eater, this diet is unconfirmed. They form schools and adapt to varying salinities, moving from freshwater as fry to saltwater as adults. They require warm water between 21 and 28 degrees Celsius and do not survive in temperate zones.
Breeding and life cycle
Females reach sexual maturity at seven to nine months, weighing around 150 grams. Males mature at a smaller size. In the Philippines, monsoon rains trigger spawning by lowering salinity and temperature. The transparent, spherical eggs measure about 0.7 mm in diameter. Larvae hatch after roughly 20 hours and pass through a pelagic tholichthys stage, similar to butterflyfishes.
Fish and people
People in its native range catch and eat this fish. It is also a popular choice for aquariums due to its hardiness. However, handlers must be careful as the anterior spines deliver a venom that causes pain and dizziness. Soaking the wound in hot water is a common treatment for stings. The fish is sometimes called butterfish or tiger scat in trade.
Questions people ask about Spotted scat
Is the spotted scat dangerous to handle?
Yes, it has small spikes in its anterior parts that can sting. The venom causes significant pain and dizziness. Soaking the affected area in hot water is a common treatment for the sting.
What does the spotted scat eat?
It is an omnivore. Juveniles prefer zooplankton, while adults are primarily herbivorous. Although its scientific name suggests it eats dung, studies have not confirmed this behaviour in its diet.
Can spotted scats live in freshwater?
Yes, they are adaptable. Fry live in freshwater environments, but as they mature, they move to saltwater. They thrive in estuaries and lower river courses where salinity varies.
Good reading and sources
- Scatophagus argus on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Scatophagus argus", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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