Autonomous Underwater Vehicles (AUVs) find a wide range of applications in marine geosciences and are increasingly being used for search and rescue, health monitoring, data collection and naval surveillance. In this research, design, fabrication and IOT control of a pH level measuring robotic fish (Fanny) is proposed. The developed robotic fish has three parts body, abdomen and tail, apart from that two hinges are provided for the independent motions of the abdomen and tail. The developed robotic fish uses a gear train for motion transmission. The modelling of Fanny is done using 3D printing using ABS material. An IOT control system is developed with our own platform using HTTP protocol. To monitor the pH level of water a pH sensor SEN0161 is used. The Chemical nature of the water was observed and was constantly pushed to the cloud on a regular time interval. Based on IOT, the response time varies according to the behaviour of the water body and the degree of turn of robotic fish is found to be dependent on the efficiency of the design. © BEIESP.