Spotted Scat (Scatophagus argus)

The Spotted Scat (Scatophagus argus) is known to tropical fish keeping enthusiasts as the Common Scat, Green Scat, Argus Fish,Butter fish, Spotted Butt, Spotted Butterfish, Spotted Scad, Spadefish, or Leopard Scat.

Although it is distributed throughout the Indo Pacific, most aquarium specimens are collected from the fresh and brackish waters in and around Thailand.

The Spotted Scat normally inhabits brackish estuaries, freshwater streams, mangroves, and natural embankments.   They start their lives out in freshwater and as they mature, move into brackish, and eventually a totally marine environment.

The Spotted Scat has a compressed, squarish body with a steeply slanted head profile.   The body is colored a shiny silver with a light greenish cast and is covered with black spots all across the body extending onto the fins.

Spotted Scat (Scatophagus argus)

Spotted Scat (Scatophagus argus)

Juveniles are more rounded in shape and become more square as they mature.   Juvenile Green Scats are brown or green with black leopard like spots over the body and some stripes on the head.   As the juveniles mature, they lose their stripes and their body color becomes silvery or bronze.

In mature adults, the spots are often faded and visible only on the back and upper parts of the fish.

In the wild, the Spotted Scat can reach a length of 15″ but in an aquarium environment, they usually grow to 6 or 8 inches in length, depending on the size of the tank.

Spotted Scats are a peaceful species that do best in groups of at least four or five.  They are lively, curious, outgoing and will quickly become tame and accustomed to the company of their keepers.

Spotted Scat (Scatophagus argus)

Spotted Scat (Scatophagus argus)

Many tropical fish keeping enthusiasts keep them in mixed schools with Monos, and except for some aggressive species, Spotted Scats will get along well with most other types of larger fish.

They will usually not bother other fish unless they are small enough to be considered on their menu.

To begin with, juvenile Spotted Scats need a tank of at least 60 gallons when they can be kept in freshwater, however, as they grow, they should be gradually transitioned to brackish and eventually salt water to keep them in top condition.    They need a fine gravel or sand substrate with driftwood branches or roots for them to hide among.   Plants can be added to their tank but will be eaten as the fish grow.

The addition of 2 to 3 teaspoons of marine salt per gallon of tank water will initially keep Spotted Scats healthy and bring out their colors.   As they mature, they require additional salt added to their water until a marine salinity is achieved.

Because Spotted Scats are sloppy eaters and extremely sensitive to nitrites, they need a good biological filtration system with plenty of water movement and swimming space to thrive.   Weekly tank maintenance with 20 to 30% water changes are also required.

In the wild, Spotted Scats feed on worms, insects, crustaceans, and plant matter.   In an aquarium environment they will eat almost anything put into their tank.   They are more herbivorous than many other brackish water species and need a good amount of vegetable matter such as algae, dried or fresh seaweed, blanched spinach or lettuce, zucchini or cucumber slices, and frozen peas. Occasional feedings of shrimp, brine shrimp, mysis shrimp, or bloodworms will keep their diet balanced.

Spotted Scats normally spawn in saltwater reefs.  Like Salmon, Eel, and Trout, the fry will swim to freshwater where they grow and then return to a more brackish or salt water environment.   For this reason, they have never been bred in captivity.

The Spotted Scat (Green Scat) and Red Scat (or Ruby Scat) are both readily available to tropical fish keeping enthusiasts however the price of the red version is usually much higher than that of the more common green variety.

Purchase size is usually around 2″ to 2 1/2″.

Spotted Scat (Scatophagus argus)

Spotted Scat (Scatophagus argus)

 

 

 

 

 

 

 

Minimum Tank Size: 60 gallons
Care Level: Moderate
Temperament: Peaceful
Aquarium Hardiness: Moderately Hardy
Water Conditions: 68-82° F, 12 – 18 dGH, pH 7.5-8.5
Max. Size: 15″
Color Form: Silver, Green, Black
Diet: Omnivore
Compatibility: Multiple species brackish water tank
Origin: Thailand
Family: Scatophagidae
Lifespan: 20 years
Aquarist Experience Level: Advanced

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  1. […] to 6 specimens will minimize aggression.   In a large brackish water aquarium, they do well with Scats, Monos, Green Chromides and other species of Archer […]


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