The mono begins its life in fresh water, with the juveniles migrating to brackish
regions as they mature. The adults are true sea-dwellers. This species requires
a large tank with enormous amounts of space for group swimming. A timid species,
it prefers live prey or fresh food. A near relative, M. sebae (the fingerfish),
is partially herbivorous. When in poor health, or when the water quality is unsuitable,
the coloration of both species darkens; normally, the silvery background predominates.
Size: 15-18 cm.