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Key silverside

Menidia conchorum

Listing Status

  • Federal Status: Not listed
  • FL Status: State-designated Threatened
  • FNAI Ranks: G3Q/S2 (Globally: Rare [classification as a separate speciesquestioned] /State: Imperiled)
  • IUCN Status: NT (Near Threatened)


The Key silverside is the smallest member of the Menidia genus (Gilbert 1992).  This species can reach a length of two inches (5.1 centimeters).  The Key silverside is silver-colored with distinct large eyes, 12-15 anal rays, 33-35 lateral line scales, and 12-14 pre-dorsal scales (Florida Natural Areas Inventory 2001)


The diet of the Key silverside primarily consists of small crustaceans and insects (Getter 1981).

Spawning occurs from mid to late winter.  The average egg mass for females is 42 eggs.  The Key silverside is a substrate spawner, which means it lays eggs on the clear surface of suitable areas.  Each egg is attached to a centralized stem by thin fibers, which keeps the eggs secure in the nesting site.  The life expectancy of the Key silverside is thought to be approximately one year (Getter 1981). 


key silverside map

The Key silverside inhabits protected, saline lagoons and ponds with restricted tidal exchange (Getter 1981, Conover 2000).  They are endemic to the lower and middle Florida Keys and have been documented in lagoons on Long, Grassy, Big Pine, No Name, Little Torch, Cudjoe, Sugarloaf, Saddle Bunch,  and Rockland Keys; Boca Chica, and Key West.


Habitat loss and alteration is a major threat to the Key silverside population.  Prime habitats have been altered and destroyed by development, hurricanes, and flooding (Getter pers. comm. 2010).  Because the lagoons and ponds occupied by Key silversides are limited, development or alteration of remaining habitat could be detrimental to Key silverside subpopulations.  Other threats include increased predation from introduced predators, such as the blue gill fish (Getter 1981).

Conservation and Management

key silverside

The Key silverside is protected as a State-designated Threatened species by Florida’s Endangered and Threatened Species Rule.

Biological Status Review (BSR)
Supplemental Information for the BSR


Conover, D.O., S. Munch, T.E. Lankford Jr. 2000. Current status of the Key silverside, Menidia  conchorum, in southern Florida. U.S. Geological Survey.  erside/Menidia%20conchorum%20FINAL-1.pdf

Florida Natural Areas Inventory.  2001.  Field guide to the rare animals of Florida.    

Getter, C.D. 1981. Ecology and survival of the key silverside, Menidia conchorum, an atherinid fish endemic to the Florida Keys. PhD dissertation, University of Miami, Miami, FL.

Gilbert, C.R.,1992. Key Silverside Menidia conchorum. Pages 213-217 in C.R. Gilbert, editor. Rare and Endangered Biota of Florida. Volume II.  Fishes. University Press of Florida, Gainesville, Florida, USA.