Silver Moony
Monodactylus argenteus
Type: saltwater, reef, brackish
Physical Characteristics
Disc-shaped, highly compressed body with silver metallic scales. Features two vertical black bands across the eye and operculum. The dorsal and anal fins are tipped with bright yellow, giving it its distinct moon-like shape.
Habitat & Distribution
Widespread in the Indo-West Pacific, including coastal areas, bays, and mangrove estuaries. They frequently move between saltwater and brackish environments.
Size & Weight
Normally grows to 15-20 cm (6-8 inches) in length, but can reach a maximum of 25 cm. Weight is typically less than 300 grams.
Similar Looking Species
African Moony (Monodactylus sebae) which has a deeper, more elongated body and more prominent vertical banding.
Ecological Role
Occupies a mid-water niche in coastal ecosystems, acting as both a predator of small invertebrates and prey for larger coastal fishes and birds.
Diet
Omnivorous; feeds on a variety of plankton, small crustaceans, detritus, and marine insects. They are active mid-water foragers.
Behavior
A highly social, schooling fish known for being very active and fast swimmers. Can be nervous and skittish but becomes bolder in groups. Diurnal activity patterns.
Reproduction
Spawning typically occurs in saltwater or brackish environments; they are egg-layers with planktonic larvae that drift with ocean currents before settling in mangroves.
Conservation Status
Least Concern (IUCN); populations appear stable across their wide geographic range.
Identification Tips
Look for the distinct diamond-shaped profile, bright yellow-tipped fins, and two vertical dark stripes near the head area.
Interesting Facts
These fish are remarkably euryhaline, meaning they can tolerate a wide range of salinity from pure freshwater to full-strength seawater throughout their life cycles.
Identified on: 5/23/2026
Mode: Standard