Raising ornament fishes in Taiwan is geajng popular. The maintenance of good water quality is very critical in successfully raising the ornament fishes. However, the contamination of water by fish feed seems to be unavoidable problem. The fish feed has more or less polluted the water before they are consumed by fishes or a certain proportion of the fish feed is completely wasted and pollutes the water severely. Therefore, it is the goal of this study to reduce the contamination by fish feed to maintain the water quality.The film coating of the fish feed is used as a means to reduce water contamination by decreasing the erosion of fish feed. Several polymers were screened for their effect in reducing the water turbidity. Chitosan was chosen because of its best effect in decreasing water turbidity. Besides, it is also a natural material from shell. Its floatability, immediate toxicity and coating process by automatic film-coating machine were also evaluated.It was concluded that the coating of fish feed with chitosan can decrease the turbidity of water, and the automatic film-coating machine can be used without damaging the hardness and friability of the fish feed. 在台灣已越來越多人養殖觀賞魚，養殖觀賞餘的成功關鍵在於其水質。在養殖期間因魚飼料所造成的水質污染，是一直無法解決的問題。魚飼料所造成的汙染，往往從魚飼料一丟水中就開始，若該飼料一直未被魚食用而留下水中，則會造成更大的污染。因此本研究的目的是想減少魚飼科對水質的污染。將魚飼料包膜可以減少魚飼料崩散及溶離，如此就可以減少水質的汙染。本研究比較甲殼素與幾種高分子材料，來找出適合為魚飼料包膜的材質，發現用甲殼素包膜的魚飼料所造成的濁度最少，而且甲殼素是從貝類所得到天然食材，因此對甲殼素的漂浮性、毒性及自動模衣機生產的可能性作進一步的了解。本研究的結論是在魚飼料外圍包上一層甲殼素可以減少水質的汙染，自動模衣機的製造對魚飼料的硬度及易碎性沒有損害。
