Abstract: A microcosm study was carried out to explore the possibility of applying garlic hydroponics to aquaculture. The experiment of planting garlic in tanks cultivating Brachydanio rerio showed that the natural mortality of Brachydanio rerio increased significantly when the initial density of garlic reached 4.75 g/L, which may be related to reduction of dissolved oxygen. The experiment of planting garlic in tanks cultivating Carassius auratusgibelio showed that planting garlic led to the significantly decreasing concentrations of total phosphorus, total nitrogen, ammonia nitrogen, permanganate index and nitrite nitrogen in water. Among these parameters, the concentrations of ammonia nitrogen showed the biggest reduction of 89.1% after 33 days of cultivation (compared with the control group). The garlic hydroponics showed a good prospect of application in aquaculture for its good effect on water purification and its potential antibacterial ability. But it is noteworthy that the planting density needs to be controlled for the low dissolved oxygen caused by high planting density.