El silver argus fish (Selenotoca multifasciata) It is a fascinating option for aquarists who wish to get into the marine aquarium or those who desire a colorful, resilient fish with dynamic behavior. This species, prized both for its resilience to variations in water chemistry and its attractive appearance, requires certain care and knowledge to successfully maintain it in captivity.
Featured photo of the silver argosi ​​fish in an aquarium
Origin, distribution and natural habitat
El silver argos fish, whose scientific name is Selenotoca multifasciata, is part of the Scatophagidae family. It is distributed across a wide geographic area that extends from the northern coasts of Australia, New Guinea, and New Caledonia, to mangrove areas, estuaries, and coastal areas of rivers and lagoons where brackish and fresh water meet. It is commonly found in the tropics of the Indian and western Pacific Oceans, and in habitats such as rivers, marshes, swamps, lagoons and mangrove areas. The sleepy fish It also shares some similar habitats in those ecosystems.
During its juvenile stage, it can inhabit both fresh and brackish waters, migrating to marine areas as it reaches maturity. This migratory characteristic allows it to adapt to changes in water salinity levels and makes the silver argus an excellent candidate for transitional freshwater/saltwater aquariums.
Morphology and physical characteristics
Stands out for its laterally compressed body and elevated appearance, with an abrupt profile that clearly separates the head from the body. Its size varies depending on whether it is wild or in captivity: in the wild it can reach up to 40 cm, while in aquarium it rarely exceeds 20 cm.
The color pattern is variable, with the predominant color being yellowish to greenish silver, although there are shades ranging from greyish silver to ochre, depending on the age and origin. It presents dark vertical lines extending from the back and fading toward the abdomen, becoming dots on the underside of the body. These patterns usually disappear in adult specimens. edges of the dorsal, anal and caudal fins They are black in color, although this tone may fade with age.
La cabeza It displays greenish and yellow tones, large, prominent eyes, a small, horizontal, non-protruding mouth, and several rows of teeth. The most notable anatomical features include:
- 12 spines y 16 soft rays in the dorsal fin
- 4 hard spines and 15-16 soft rays on the anal fin
- Pectoral and ventral fins aligned vertically
- Compressed body with a hexagonal outline typical of the scatophagic family
An important detail is that its dorsal spines contain venom, not lethal to humans, although they can cause intense pain if accidentally punctured.
Behavior and sociability
El silver argos fish it's a kind gregarious, which means that he prefers to live in groups or schoolsKeeping them alone can lead to stress and erratic behavior. Their behavior is active and curious, so they enjoy swimming in large spaces and require aquariums with clear areas to move freely.
Being sociable and non-aggressive, they can coexist with other species with peaceful behavior and similar aquatic needs, although coexistence with slow-moving or long-finned fish should be avoided, as the silver argus can nibble them. Angelfish also requires community care.
Ideal aquarium conditions
Given his adult size and the need to live in groups, the optimal aquarium should be spacious: not less than 400 liters for a group of specimens. It is recommended:
- Provide free space in the front for swimming
- Decorate with roots, rocks and shelter areas
- Maintain adequate aeration and water movement, since stagnant water has less dissolved oxygen.
- Avoid overloading delicate plants, especially juveniles, as they are easily devoured.
Although in nature they are associated with areas with vegetation, in aquariums they hard-leaved or artificial plants They can help recreate the environment, but care must be taken to ensure that they are not pulled out or eaten. The kissing fish They can also be part of an aquarium with compatible species.
Water parameters and fresh-brackish-marine transition
One of the peculiarities of this species is its ability to withstand fluctuations in salinity, which is useful for hobbyists who want to learn about adjusting aquatic parameters:
- youth: They prefer fresh or brackish water, moderately hard (up to 14º KH), slightly alkaline pH (up to 8,0).
- Adults: They require progressive addition of sea salts, reaching densities of between 1,020 and 1,024 to recreate marine conditions.
- Temperature: Must be kept between 20 and 28 ° C at all times.
A recommended method for a brackish aquarium is to mix four parts fresh water to one part sea water, achieving a density of approximately 1,005 and pH 7,6 for juveniles. As the fish grow, the salt concentration must be increased until marine levels are reached for adults. Sailfish They also withstand changes in salinity at different stages of their life.
Water must be renewed regularly and it is crucial to have a efficient biological filtration system, since the silver argus fish is sensitive to nitrogen compounds such as ammonia and nitrites, especially in alkaline water. Proper filtration and a strict cleaning routine prevent their buildup and possible poisoning.
Diet: specialized omnivorous diet
El silver argos fish It is omnivorous, with a varied diet that allows it to adapt both in the wild and in an aquarium. Its diet includes:
- Plant food: lettuce, spinach, chard, oat flakes and seaweed such as Porphyra umbilicales, Porphyra yesoensis y Palmyra palmata.
- Commercial foods: granules, sticks, tablets and flakes, especially if they are accustomed from a young age.
- Live or frozen food: mosquito larvae, mysis, small fish and invertebrates.
- Cooked rice and other cooked vegetables.
In the wild, they also ingest organic debris and occasionally the droppings of birds and other fish, which contributes to their ability to manage different osmotic conditions. In aquariums, however, it is important to prevent them from ingesting droppings, as they may contain toxic ammonia.
Differences with similar species
El silver argos fish It can be confused in its juvenile phase with Scatophagus tetracanthus y Scatophagus argusKey differences include:
- More elongated body in the silver argus
- Narrower interradial membranous space of the fins
- Hexagonal outline and longer caudal peduncle, covering one-fifth of the length of this fin
- Pointer mouth and proportionally larger eyes
In adulthood, the bar and dot coloration fades, simplifying and making it easier to identify compared to other species.
Differences between sexes and reproduction
Does not exist apparent sexual dimorphism In the silver argosi, that is, males and females do not present easily perceptible external differences. Successful reproduction in captivity is not documented, and there are two theories regarding spawning:
- Adults migrate to rivers to spawn and return to the sea when they reach a certain maturity.
- Spawning occurs at sea on reefs and the fry travel up rivers to grow.
For the time being, controlled reproduction of silver argos fish remains a challenge for the aquarium hobby.
Importance in aquaristics and selection for beginners
This fish has gained fame as one of the more durable and educational options For those who wish to move from freshwater to marine aquariums. Its adaptability and tolerance to various variations in water chemistry allow hobbyists to practice parameter manipulation without risking their health. de peces delicate. The flower horn fish It is also an example of species that require attention in aquarium adaptation.
Their maintenance has been documented in the evolution of aquaristics, from the first ornamental ponds to modern reef aquariums, where the number is limited. de peces and the integration of live rock and invertebrates is prioritized to simulate more stable natural ecosystems teeming with life.
El silver argos fish It is a gem in the aquarium hobby, not only for its unique beauty and striking color contrasts, but also for its gregarious behavior and adaptability. Whether as a first-time visitor to brackish and marine aquariums or as a standout specimen in large community aquariums, this fish requires special attention in aspects such as tank volume, water quality, and dietary diversity. Choosing one guarantees dynamism and constant learning, as long as its biological needs are respected and a healthy group coexistence and a stimulating environment are encouraged. Tetras They are also popular in community aquariums for their hardiness and color.
