Order Perciformes
Family Scatophagidae
These fish have a deep, laterally compressed body and a small mouth. They inhabit the tropical waters of the Pacific and Indian Oceans – in coastal areas, being common in shallow lagoons and estuaries, and are adapted to brackish water where they can tolerate significant freshening. They inhabit river deltas where fresh water mixes with sea water. Juveniles are often found even in completely fresh water.
They grow up to 30 cm, live in schools, and feed predominantly on plants. Since they can consume green food in very large quantities, which is related to their metabolism and digestion and does not contribute to the cleanliness of the aquarium water, it is necessary to provide a powerful filter.
The smallest species in the family are considered to be Selenotoca multifasciata (Richardson, 1844) and Selenotoca papuensis (Fraser-Brunner, 1935). Of these, the former inhabits the southern coast of Australia, while the latter lives in the coastal waters of New Guinea and Sulawesi (Celebes), and is also known off the coast of Central Europe. The universally recognized “giant” is Scatophagus tetracanthus.
Genus Selenotoca.
— Spotbanded scat, Striped scat, Silver scat — Selenotoca multifasciata [Richardson, 1846]. Synonym: Scatophagus multifasciatus. (English: Silver Scat, Spotbanded Scat, Striped Scat). Indonesia, Australia, New Guinea. Inhabit river mouths and coastal waters. Juveniles are often found in mangrove waters or freshwater rivers, whereas mature specimens prefer salt water. Up to 35 cm, in aquariums up to 25 cm.
The body is flat, highly compressed, especially at the back; the head is clearly separated from the body with a steep profile, and the mouth is small. The dorsal and anal fins are divided into two parts. Fin spines are very sharp and venomous. Pectoral and pelvic fins are located one below the other. Juveniles are often confused with S. tetracanthus and S. argus.
Body coloration ranges from yellowish to olive-silver, although depending on age and origin, it can vary from light grey to ochre. The back and part of the head are greenish-yellow. The lips are outlined with black stripes. The upper part of the body has 7-12 vertical black stripes that taper downwards, where they are replaced by small, round spots of the same color. The edges of the caudal, dorsal, and anal fins have a black border. This edge coloration on the fins disappears over time.
A pair of fish requires an aquarium of at least 150 liters with plenty of swimming space. A group of 6-10 individuals of these contrastingly colored fish looks wonderful in a spacious aquarium with a dark substrate and plenty of decorations made of rock piles and driftwood, supplemented with synthetic greenery. Live aquarium plants will be destroyed.
Dark-colored medium or large gravel can be used as a substrate. Despite their formidable appearance, these fish are completely peaceful and lead a schooling lifestyle; they can coexist with other brackish-water species of similar size. They may be aggressive towards newly introduced fish.
Juveniles can be kept in a brackish-water tank with any non-predatory fish requiring similar conditions. Common salt should be added to the water in a proportion of 1 teaspoon of salt per 5 liters of water, gradually increasing the concentration as the fish grow.
The aquarium must have a highly efficient water filter and enhanced aeration. A weekly replacement of 1/3 of the aquarium water with fresh water is necessary. Water changes must be taken very seriously, as the well-being of the fish strongly depends on its composition.
Adult selenotocas need to be moved to a marine aquarium. The minimum aquarium volume is 300 liters per pair. They consume all types of high-quality animal and plant foods. At least half of the fish’s diet should consist of plant-based foods. Prone to overeating, they require fasting days and strict quantitative limits on their food supply.
They reach sexual maturity at 4-5 years of age. They do not breed in aquarium conditions. Lifespan in an aquarium is about 15-20 years. Temperature 20-28°C, dH up to 30°, pH 7-9, salinity from 10‰.
Identification: Spotbanded scat — Selenotoca multifasciata.
Scatophagus argus, Scatophagus tetracanthus.
Monocirrhus polyacanthus, Polycentrus schomburgki. 
