Inland Silverside, Menidia beryllina

Inland Silverside, Menidia beryllina. Fish caught from coastal waters off Belize, October 2012. Length: 7.6 cm (3.0 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan. Note:  this fish has significantly different characteristics than the other three fish photographed herein – longer snout, more streamlined body, black lateral line and the identification should be considered as tentative. Might also simply be a Juvenile Inland Silverside.

Inland Silverside, Menidia beryllina. Fish caught from Lake Fort Phantom Hill, Abilene, Texas, June 2021. Length: 7.6 cm (3.0 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Inland Silverside, Menidia beryllina. Fish caught from coastal waters of Long Island, New York, October 2021. Length: 7.6 cm (3.0 inches). Catch, photograph and identification courtesy of James Lafontaine, Long Island, New York.

Inland Silverside, Menidia beryllina. Fish caught from a coastal steam in Galveston, Texas, July 2020. Length: 7.6 cm (3.0 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

Inland Silverside, Menidia beryllina. Fish caught from Tempe Town Lake, Tempe, Arizona, June 2020. Length: 8.1 cm (3.2 inches). Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.

Inland Silverside, Menidia beryllina. Fish caught from a man-made pond in Phoenix, Arizona, June 2020. Length: 8.7 cm (3.4 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

The Inland Silverside, Menidia beryllina, is a member of the New World Silverside or Atherinopsidae Family, and is known in Mexico as plateado salado. Globally, there are ten species in the genus Menidia, of which three are found in Mexican waters, all within the coastal waters of the Atlantic Ocean.

The Inland Silverside has an elongated narrow body that is six to seven times its length. They are an overall silvery color being greenish dorsally with crosshatching and yellowish on their sides and translucent greenish ventrally with a midlateral silver stripe. Their snout and lower jaw are covered with small black spots and the sides of their head and rear of the body below the lateral line are bright, iridescent silvery white. Their fins are clear. Their head is large and flattened dorsally with disproportionately large eyes, a short snout, and an upturned terminal mouth that is equipped with well-developed teeth set in bands. Their anal fin has 1 spine and 16 to 19 rays that is strongly concave with a long base; their caudal fin is forked; their first dorsal fin has 4 to 6 spine and 8 or 9 rays and originates before the anus; their second dorsal fin has 4 or 5 weak spines and is widely separated from and smaller than the first; their pectoral fins have 12 to 14 rays; and, their pelvic fins have 6 rays and are closer to the pectoral fin base than the anus. They are covered with smooth cycloid scales.

The Inland Silverside is a schooling pelagic species found in shallow intertidal, brackish and freshwaters at depths up to 30 m (100 feet). They are known to extend far up river. They have the ability to tolerate a wide variety of salinities providing them with numerous types of habitats. They reach a maximum length of 15 cm (5.9 inches) with the females growing faster than the males. They are active daytime feeders that consume diatoms, fish eggs and larvae invertebrates, terrestrial insects, and zooplankton. In turn they are heavily preyed upon by the Black Crappie, Pomoxis nigromaculatus, Largemouth Bass, Micropterus salmoides, White Crappie, Pomoxis annularis, and various birds. The move to in large dense schools to shallow water areas at night in areas with heavy structure for protection and then move offshore at dawn to feed for a couple of hours and then return to shallow waters. They will repeat these migrations late afternoon for feeding. Reproduction is oviparous and occurs in both tidal freshwater and brackish waters. Each female release between 200 and 2,000 masses of sticky eggs several times per year. These eggs attach themselves to shallow water seaweed via long filaments and are then fertilized by males and hatch in 6 to 10 days. The larvae are planktonic. They are prone to massive mortalities during warm water episodes and while breeding. They have life spans of two years. The Inland Silverside is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Inland Silverside is found in Mexican waters along the northern coast of the Gulf of Mexico from the Texas boarder south to the Rio Panuco and Laguana de Tamiahua in Vera Cruz.

The Inland Silverside is similar to and can be confused with the Tidewater Silverside, Menidia peninsulae (larger in stature, margin of a anal fin is straight; widely spaced dorsal fins).

From a conservation perspective the Inland Silverside is currently considered to be of Least Concern with stable, widely distributed populations. They are very small in stature and are of limited interest to most, however, they have been widely introduced as a forage fish and are an important food source for a wide variety of fish, marine mammals, and sea birds. They have been widely introduced in the United States to control gnats and midges. They have also been utilized as in indicator of acute marine aquatic toxic environments of marine and estuarine organisms. They are utilized by recreational anglers as a live bait on a limited basis.