This research deals with the monitoring techniques using normal and multi-spectrum cameras to detect coral healthiness. The Acropora Corals were investigated in laboratory experiment. Parameter of investigation is Ammonia contamination from 0.01 ppm to 10.0 ppm. Under these conditions, the images of coral were captured and analyzed. An Entropy and coral indices of the obtained images were proposed. The important finding in this study is the feature extraction of coral healthiness: (1) event detection, (2) % degradation and (3) relationship between coral index and entropy. For event detection, the trends of water quality parameters such as temperature and salinity was considered. The obtained entropy values gave % degradation of coral. It was also found that GRCI index related with the relevant entropy values of coral images.