Spawning season: Menidia beryllina collected from Lake Texoma, spawn throughout April, May, June and (depending on lake temperature) during July (Hubbs 1982). In Texas, sexually mature females were reported February - August, with spawning peaks during spring and late summer (Middaugh and Hemmer 1992). During late March-early July along the Mississippi Gulf Coast at water temperatures of 23.9-32.7 degrees C (Garwood 1968; Hubbs 1976).
Spawning habitat: Shallow water in areas with abundant vegetation (Hildebrand 1922). Spawning occurs during both day and night (Middaugh et al. 1986). In some populations, spawning occurs mostly in midmorning (Hubbs 1976).

Fecundity: In Lake Texoma, M. beryllina females lay eggs daily at ca. 1000 hour; egg compliment consists of ca. 7.5% of the female’s biomass; female fecundity size-dependent with average-sized females producing ca. 835 eggs daily, large females ca. 2000 eggs and small females ca. 200 (Hubbs 1982). Fertilized eggs are about 0.75 mm in diameter and have a tuft of gelatinous threads attached to the outer membrane. Eggs hatch in 6 days at a water temperature of 27.8 degrees C and in 10 days at 25 degrees C (Hildebrand 1922). Hatching delayed at water temperatures below 19 degrees C (eggs hatch in about 30 days at 14 degrees C), which may cause embryos to exhaust nutrient supplies and starve to death prior to hatching (Hubbs et al. 1971). Development time and hatching success apparently independent of salinity for M. beryllina in coastal waters (Middaugh et al. 1986), but this is not the case for fish in freshwater areas (Hubbs et al. 1971).

Food habits: Planktivore; particulate feeder; size-selective picker; main food item zooplankton (Saunders 1959; Goldstein and Simon 1999). Stomachs of adults in west Tennessee contained food items included midge larvae, mayfly larvae (Hexagenia), and fallen terrestrial insects (including Homoptera, Hymenoptera; Etnier and Starnes 1993). Morris (1982) reported M. beryllina collected from Lake Conroe, Texas, fed mostly on zooplankton at all sizes. Major food organisms in the diet were from the following groups: Sididae, Chydoridae, Ceriodaphnia, Bosmina, Cyclopoida, nauplii, and Ostracoda.  Species fed predominately upon cladocerans (60% of total number of food organisms, with largest category, Sididae, representing 32%). Individuals 60-69 mm long fed upon Tendipedidae sub-imago to a greater degree than did smaller fish. Bettoli et al. (1991) reported consumption of fish eggs, in Lake Conroe, Texas. M. beryllina feeds during daylight hours (Wurtsbaugh and Li 1985).
Generation: > 2 years
Temperature_spawning: 30°C