This study was conducted in My Hoa Hung village in Long Xuyen city, An Giang province, Mekong River in Vietnam during August to December 2007, to assess environmental impacts from feeds used in aquaculture systems such as intensive fish cages, pens and ponds culture on and in the vicinity of Mekong River, Vietnam (e.g. Pangasius Hypopthalamus, Colossoma macropomum species). Moreover, the purpose of this study is to investigate the effects of feeds in the intensive aquaculture systems towards water environment. The study was commenced by a field survey of 20 Pangasius cage farmers, 18 Pangasius pond farmers, 20 Pangasius pen farmers and 15 Colossoma cage farmers.The survey showed that the fish density is quite high of 80-105 fish/m2 as compared with the optimum range of 30-60 fish/m2. There are three kinds of popular feeds such as homemade, pellet and Pangasius waste used in this area. The pellet feed is more effective in terms of economic profit, less environmental pollution, better product quality and reduction in trash fishes from nature.Water quality of the river is still in the limit for fish culture in three surveyed months.