Day of hatch tidewater silversides, Menidia peninsulae, were stocked at 5 fish per liter in 3l of seawater at 30 degrees/oo and raised for 16 days at 20 degrees, 25 degrees and 30 degrees C. Food organisms (Branchionus sp. or Artemia nauplii) were maintained at 500, 1,000, 5,000 or 10,000 food organisms/l. The influence of food density on growth of larval M. peninsulae was temperature dependent. At 20 degrees C, there was no difference in final size of fish based on food densities. At 25 degrees C, there was an increase in final body size as food density increased from 500 to 5,000/l. At 30 degrees C, there was an increase in final size as food density increased from 1,000 to 5,000/l. There were no significant differences in survival between food densities in tests at 20 degrees, 25 degrees or 30 degrees C. However, for any given temperature and food density, differential survival patterns were significant in explaining variance in final size between replicates. Optimal culture conditions for larval M. peninsulae were determined to be 5,000 food organisms/l at 25 degrees C.