Abstract: Indoor experiments were carried out to investigate the intercepting effects of im-movable bubble curtains(IBC)with different density on Fugu rubiripes. The density of IBC was decided by air- hole spacing,air- hole diameter and air pressure. The air- hole spacing
of each IBC was 2. 5 cm and 5. 0 cm, the air- hole diameter was 1. 0 mm and the air pressure was 21. 57, 27. 46, 33. 34 and 39. 23 kPa respectively. The IBC was under-taken from a hard polyethylene pipe(16 mm i. d),fixed on the bottom middle of an experi-mental tank. The results show significantintercepting effectsof the eight IBC on the fish be-haviors observed, and the one with air- hole diameter 1. 0 mm, air- hole spacing 2. 5 cm and air pressure 27. 46 kPa was the best. The average obstructing rate was 71. 0%.