DOI: 10.36347/sajb.2014.v02i12.006

Pages: 877-881

The cultivation of Indigo Fish (Oreochromis niloticus) in the floated-net cages is the activity using water body of Tondano Lake. However, it contributes to environmental pollution due to fish food-induced turbidity. Some portions of food are not used by the fish and only discharged to the waters. The objective of research is to analyze the kind and mechanism of environmental friendly feeding with laboratory experiment approach. The analysis is conducted over the nutrient in three types of general food used by the cultivator of Indigo Fish (Oreochromis niloticus) in the floated-net cages along the coasts of Tondano Lake in North Sulawesi Province. The kinds of general foods observed are Food A (Nitrogen 4.62 %, Phosphorus 1.62 %), Food B (Nitrogen 4.75 %, Phosphorus 1.27 %) and Food C (Nitrogen 4.48 %, Phosphorus 1.28 %) at dose 3 % of body weight per day. Food A, Food B, and Food C are not physically different. The laboratory experiment shows that the dissolvability rates of Food B and Food C are lower than Food A. Remnants of Food B and Food C settled on the base of aquarium are still intact. It does not influence or change water quality. Food A settled on aquarium base leaves white grains. Result of experiment indeed shows that physical quality of water for the cultivation of Indigo Fish (Oreochromis niloticus) fed with Food A is more turbid than those with Food B and Food C. Other difference is also found on the feces released by Indigo Fish (Oreochromis niloticus). Fishes fed with Food A have their feces colored white, while those fed with Food B and Food C have their feces in similar color to food color. Results of laboratory analysis at Balai Riset Standarisasi Industri Manado (BARISTAND) indicate that nitrogen rate in the feces of Indigo Fish (Oreochromis niloticus) fed with Food A is higher (0.48 %) than those fed with Food B (0.21 %) and Food C (0.53%). High nitrogen rate in the feces of fishes feed with Food A (0.48 %) means that this Food contributes to