This paper deals with the physical and chemical characteristics of two highlyproductive small lakes in the suburbs of Wuhan Shi in 1973. Some regularitiesconcerning the relationship botween these characterstics and the richness of thenatural food resources are recorded. In connection with the problems that arise fromthe fish farming, special investigations are made with respect to some of the quantita-tive indexes for the adequancy of the water fertility in the small lakes. Relavantequations are proposed. The essential analytical records are concluded as follows: 1. During the fish farming seasons, the quantity of dissolved oxygen is generallyfound to be 7mg/l. The oxygen content at the bottom layer is usually lower thanthat at the surface. 2. A proportion exists between the total nitrogen and the amount of ammonia.The sensonal fluctuation of the total phosphorus is similar to that of the nitrogen. Aquantitative relationship also exists between the amount of phosphate and the totalphosphorus. 3. The quantity of the aquatic micro-organisms decreases geometrically as thewater temperature rises. 4. There is a high density of phytoplankton, which has a lagged effoct on theutilization of nitrogen. It also bears a quantitative relationship with the change of theratio of nitrogen to phosphate. When the water blooming occurs and the nitrogencontent reaching to a sufficient concentration, the N/P is about 10-17. 5. There are also large amount of protozoa and rotatoria, and the seasonalfluctuations of their standing crops are directly related to the total phosphate content.Crustacea ns are few in species and low in quantity, and shows no clear relationshipto the nitrogen content. 6. The biomass of zoobenthos is quite low. There are only a few aquatic oligo-chaetes and chironomid larvae. No molluscs are found- 7. When the total nitrogen content is 6-8mg/l it denotes that the fertility ofthe water reaches to the critical value. 8. While a decreases of 1 mg/l of dissolved oxygen at the surface layer, it meansa decrease of 1.35mg/l at bottom laryer. So that when the amount of dissolved oxygenat the surface is as low as 2 mg/l, the oxygen of the bottom layer will be completelyexhausted lack of oxygen.