In Singapore, the salt concentration used for packaging ornamental ¢sh is 0.5^3.0%,whichismuch
lower than 9% recommended by Cole, Tamaru, Bailey, Brown & Ako (1999). The experi ment with guppy showed a drastic increase in the total ammonia content when the salinity of transport water was increased to 3% or 9%, due to a decrease in the e⁄ciency of clinoptilolite (Fig. 6). These results suggest that among the three e¡ective salinities ranging from 1% to 9%, guppies should be packed at 1%.Higher salinity should be avoided as it may result in undesirable quality of the transport water.