Atherinella milleri

Common Name

Miller's Silverside

Year Described

Bussing, 1979


Dorsal Fin: IV; I, 5-8
Anal Fin: I, 23-27
Pectoral Fin: 12-14
Lateral Line Scales: 40-45
Predorsal Scales:
Circumferential Scales: 21-25
Transverse Scale Rows: 7-9
Gill Rakers: 19-29 (lower arch)

Body elongate, flat dorsally, and compressed laterally, with two dorsal fins. Eye large. Mouth terminal, strongly oblique, and does not reach the orbit. Premaxilla protractile. Distal end of premaxilla expanded. Premaxilla lacks postmaxillary process. Teeth in both jaws. Rostral sensory system present. Anterior portion of sensory system with 4 separate pits. Dorsal fins well separated. Spinous dorsal fin origin behind anal fin origin (above anal ray 6-8) and soft dorsal origin above anal fin ray 16-18. Anal fin long. Sheath on anal fin absent. Pelvic fin origin well behind pectoral fin base. Axillary scale present (half pelvic length). Pectoral fin long, strongly falcate and high on body. Caudal fin forked. Scales cycloid.


Translucent grayish overall, paler ventrally. First few scale rows with dark cross-hatches. White highlights pn the head and gut. Lateral stripe thin and silvery. Fins gray to clear. Eye silver.


Maximum size to over 120mm SL.


A brackish water, estuarine species found in marshes, lagoons, and mangrove forests.


Belize to Costa Rica.


Chernoff, B. 2002. Atherinopsidae (pp 1090-1103). In: Carpenter. 2002. The living marine resources of the Western Central Atlantic. Vol. 2: Bony fishes part 1 (Acipenseridae-Grammatidae). FAO Species Identification Guides for Fisheries Purposes. American Society of Ichthyologists and Herpetologists Special Publication No. 5.

Other Notes

A distinctive species easily separated from other Atlantic marine/brackish species of Atherinella due to the extreme forward position of it’s anal fin compared to all relatives and the unique rostral sensory structures. It’s closest relatives are Mexican freshwater species (A. marvelae and A. hubbsi).