TankBud

Spotted scat

Scatophagus argus

Also known as Green scat, Argus fish, Spotted butterfish

BrackishSaltwaterFish

Spotted scat (Scatophagus argus)
Guérin Nicolas (messages) · CC BY-SA 3.0

Care at a glance

Temperature
72–82°F
22–28°C
pH
7.5–8.5
Adult size
11.8 in
30 cm
Minimum tank
159 gal
600 L
Temperament
Mostly peaceful
Social behavior
Schooling
Tankmates
With caution
Swim level
Middle
Diet
Omnivore
Difficulty
Difficult
Breeding
Hard
Rarity
Common
Reef safe
Not reef safe
Family
Scatophagidae
Origin
Indo-Pacific estuaries, harbours, and mangroves from India and Southeast Asia to Australia and the western Pacific

Overview

The spotted scat is a large estuary fish for a big brackish or marine tank. It is a fish for experienced keepers.

Did you know

The spotted scat carries a genus name, Scatophagus, that literally means dung-eater. In the wild these fish scavenge around harbor and sewage outfalls and in mangrove mud, where they help clean up organic waste.

Caring for the spotted scat

Spotted scats are large, boisterous grazers, and a group needs at least 159 gal (600 L) with a long open footprint. Give them open swimming space and heavy filtration. Use hardy plants or none, since they graze and uproot soft greenery.

Keep the water hard and alkaline, at 72 to 82°F (22 to 28°C) and a pH of 7.5 to 8.5. Raise the salinity gradually as they grow, since juveniles handle low brackish water and adults trend toward high brackish and marine water. Keep the water clean and stable, and do not read their hardiness in the wild as a license to skip maintenance.

Spotted scats are hungry omnivores that lean heavily vegetarian, with a big appetite for greens and a habit of grazing constantly. Feed a mostly plant-based diet rather than the meaty foods people assume a large fish wants. Offer blanched greens, algae and spirulina alongside some meaty foods to prevent diet-related problems.

Keep them in a group of at least five or six, since a shoal is calmer and more confident than lone fish. Spotted scats are mostly peaceful, but they can be pushy and nip fins when crowded or underfed. House them with similarly robust brackish tank mates like monos and archers, and skip small, delicate fish.

Handle spotted scats with care. They are pelagic spawners and are not bred in home tanks, so the fish sold are wild-caught juveniles.

Good to know

The spotted scat, Scatophagus argus, is a deep, roughly disc-shaped fish in the family Scatophagidae. It grows larger in the wild than in aquariums. It has venomous dorsal spines that give a painful sting.

In the wild

Spotted scats live in estuaries, harbors, river mouths and mangrove swamps across the Indo-Pacific. Their range runs from India and Southeast Asia to Australia and the western Pacific. They often live in silty, nutrient-rich tidal water, and they are famously tolerant of dirty, variable conditions.

Common questions

What size tank does a spotted scat need?

A spotted scat needs at least 159 gal (600 L). It spends most of its time in the middle.

What temperature and pH does a spotted scat need?

A spotted scat is comfortable at 72–82°F (22–28°C) with a pH of 7.5–8.5.

What does a spotted scat eat?

A spotted scat is a hungry omnivore that leans heavily vegetarian. Feed a mostly plant-based diet of blanched greens, algae and spirulina, alongside some meaty foods.

How big does a spotted scat get?

An adult spotted scat reaches about 11.8 in (30 cm).

Does a spotted scat need a group?

Yes. A spotted scat is a schooling species and should be kept in a group, not singly.

How does a spotted scat breed?

Spotted scats are pelagic spawners and are not bred in home tanks. The fish sold are wild-caught juveniles.

Related species