Zebrafish (Danio rerio) embryos were subjected to different physical stresses, consisting of a static and two low frequency magnetic fields, and two radiofrequencies. Embryos were exposed to static (Bo, 0 Hz), very low frequency (VLF, 0.2 Hz), low frequency (LF, 270 kHz), very high frequency (VHF, 100 MHz), and ultra-high frequency (UHF, 900 MHz) magnetic field irradiation for up to 5 days. The field intensities were 40 mT, 40 mT, 470 µT, 240 nT and 240 nT, respectively. Untreated embryos were used as control.(n= 10 for each condition).