Tetrodotoxin (TTX) and its deoxy analogs, 5-deoxyTTX, 11-deoxyTTX, 
6,11-dideoxyTTX, and 5,6,11-trideoxyTTX, were quantified in the tissues of three 
female and three male specimens of the marine puffer fish, Fugu niphobles, from 
the southern coast of Korea, and in the whole body of the brackishwater puffer 
fishes, Tetraodon nigroviridis (12 specimens) and Tetrodon biocellatus (three 
specimens) from Southeast Asia using LC/MS in single ion mode (SIM). 
Identification of these four deoxy analogs in the ovarian tissue of F. niphobles 
were further confirmed by LC/MS/MS. TTX and 5,6,11-trideoxyTTX were detected in 
all three puffer fish species as the major TTX analogs, similar to Japanese Fugu 
pardalis. While 6,11-dideoxyTTX was also found to be a major analog in almost 
all tissues of Korean F. niphobles, this analog was minor in the two Tetraodon 
species and Japanese F. pardalis. Among the tissues of F. niphobles, the 
concentrations of TTXs were highest in the ovaries (female) and skin (female and 
male).