Chiang Mai Journal of Science

The low survival rate is the main issue on marine ornamental fish trading due to improper acclimatization. So far, the drip-line method is the most practical method. However, the approach is not efficient and harmful for fish close to a threshold of death. This research introduced a new acclimatization method, combining pH and carbonate hardness regulation, allowing direct and safe fish transfer from contaminated packing water to the water system. The objective of this research was to increase the survival rate through pH and carbonate hardness regulation at an industrial scale. This research was conducted by factorial design. The low pH method was performed by lowering the pH of new and clean water, combined with two levels of carbonate hardness. Six species representing marine ornamental fish types were tested. There was no significant difference (p>0.05) on the survival rate among the species. The difference was somewhat correlated to the acclimatization method and the carbonate hardness level. The highest survival rate was performed by the low pH method (99%) and significantly higher (p=0.000) compared to a drip-line method (78.91%) and conventional method (44.07%). Regarding carbonate hardness, high carbonate hardness showed a significantly higher survival rate (p=0.000) than the normal carbonate hardness.  Thus, the best method is the combination of low pH method and high carbonate hardness.