New York Natural Heritage Program
Inland Silverside
Menidia beryllina (Cope, 1867)
Ray-finned Fishes

Identifying Characteristics [-]
The inland silverside is a small fish, approximately 2 to 4 inches (5 to 10 cm) in length (Carpenter 2002). The upper sides are yellow to olive in color and the underside is pale to translucent yellow. A thin metallic-silver stripe runs along the length of the body. The dark lateral line is composed of a series of pits in the lateral scales. The posterior end of the dorsal fin is directly above the posterior end of the anal fin. The tail is slightly forked. The eggs are generally smaller than 0.04 inches (1 mm) and have filaments that help them to adhere to aquatic vegetation and to each other (Smith 1985, Weinstein 1986).

Characters Most Useful for Identification [-]
The pit-like lateral line composition and the posterior margin of the dorsal fin being directly above the posterior margin of the anal fin are the most useful characteristics in distinguishing the inland silverside from the Atlantic silverside (Smith 1985).

Behavior [-]
The inland silverside is a short-lived schooling fish, rarely living past its first breeding season. In the northern range, inland silversides generally have one spawning season per year, but in the southern range, they can have two spawning seasons per year (Middaugh and Hemmer 1992). Females produce eggs (200-1000 depending on size) and spawn daily throughout the spawning season (Hubbs 1982). The majority spawn and die their second summer of life and few survive to their second winter. After the eggs are laid, they hatch in 4-30 days, depending on water temperature (13-34 degrees Celsius) (Middaugh and Hemmer 1992).

Diet [-]
Inland silversides feed during the day on various copepods, mysids, amphipods, isopods, and insects. They generally take their prey in the water column, but the presence of sand in the stomachs of some specimens indicates that bottom feeding does occur (Weinstein 1986).
Inland Silverside Images
click to enlarge
The Best Time to See
In New York, inland silversides can be found in tidal salt marshes along Long Island Sound and in the lower Hudson River throughout the year. The reproductive season starts in April and continues through July (Middaugh and Hemmer 1992).
J F M A M J J A S O N D
Active Reproducing
The time of year you would expect to find Inland Silverside active (blue shading) and reproducing (orange shading) in New York.
Similar Species
  • Atlantic Silverside (Menidia menidia)
    In the Atlantic silverside, the posterior margin of the dorsal fin is in front of the posterior margin of the anal fin, the lateral line is composed of tubes passing through the lateral scales, and the lateral scale count is higher than in the inland silverside (Smith 1985).