ABSTRACT
The use of Artemia salina nauplii as live food has significantly aided culture of commercial fish and shrimps in recent years. However, reported deficiencies in the nutritional value of some strains originated the study of freshwater fairy shrimps as an alternative to Artemia. This study presents cyst biometry for Dendrocephalus geayi and D. spartaenovae (Anostraca: Thamnocephalidae), and the effects of some physicochemical variables on cyst hatching. The biometric characteristics of D. geayi and D. spartaenovae are within the size range of commercial Artemia strains. Favorable conditions to hatch D. geayi are 30 degrees C and conductivity near that of distilled water (<5 micromhos). For D. spartaenovae, these conditions are 28 degrees C and 280 micromhos. A very low salinity such as 1 per thousand inhibits hatching in both species.