Bangladesh is considered one of the most suitable regions for fisheries in the world, with the world's largest flooded wetland and the third largest aquatic biodiversity in Asia after China and India. Fish firming has brought a significant changes in the economy of the country. But it is a matter of great sorrow that, most of owners of the fisheries in our country are not well educated enough or they don’t have enough knowledge about the firm water. So every year a large number of fisheries counts losses in business due to death of fishes for non-suitable water in the firm. In 2018 total 1200 tones of fishes died in 4 districts reported by fisheries and livestock secretary.

The quick growth of economy brings new problem for our environment. One of the main problem we are facing is the water pollution. The most water quality factors are dissolved oxygen, total ammonia nitrogen, nitrite, PH, Alkalinity, Co2, salinity, iron, chlorine, hydrogen. These parameters have certain standard values for the fishes to live in the water. If the dissolved oxygen is below of the standard value the fishes cannot survive in water. Another parameter is ammonia in the water and it has to have certain standard level for the fishes to lives else fishes will die in one night. The temperature of the water is also important parameter for the fishes to live. Another important parameter is the PH level which has to have standard value for the fishes to live as well. The main reason of fish death is considered to be due to lack of standard values of the parameters in water as mentioned earlier. In our country the water of most of the rivers and ponds close to Dhaka city are seriously polluted. The main reason for this is the waste materials of the industries. This is usually noticed near the Dhaka city and other city areas of Bangladesh. In our country, there are many leather processing companies near the Dhaka and other districts which are close to Dhaka. These companies don't process their waste materials properly. Due to not proper processing technique and management the waste materials and contaminated water of these industries fall into the rivers and nearby ponds which pollute the rivers and pond's water seriously. In addition, our country there are nearly 7000 garments factories. They also don't properly manage their waste materials although there is pressure from proper authority but it is not possible to control this issue by the authority. The waste polluted water from the garments industries are not purified properly. Therefore waste materials and contaminated water from different industries fall into the rivers and nearby ponds which pollutes the water. This ingredients of the waste contaminated water form garments industries, leather processing industries and other industries pollute the water which have very bad effects to the aquatic creatures and also human health. It is very urgent to take necessary action to monitor and prevent the water pollution. Due to the above mentioned reasons the quality of the elements of water such as dissolved oxygen, Nitrogen, pH ,water temperature, nitrite, ammonium, Co2 do not have standard value. This causes serious problem for the fishes to live in the water. It also has bad effect to the environment and human health.

The main objective of this paper is to propose a smart IoT based water sensor system which will efficiently measure quality parameters of the water. There will be various sensors to measure different parameters of the water. This system will help us to monitor the parameters of water quality and pollution level of water which can help to prevent the water pollution. However there will be Arduino UNO microcontroller to receive the data from different sensors and process them. Wireless module will be integrated with the system as well. These measures parameters bys the various sensors will be stored in the cloud and from there they will be displayed on the Mobile application. Data also can be displaced in the website. An android mobile application will be developed for this system. The application of this proposed system is not limited to only fish farming in Bangladesh but it has other applications in many areas. This system can be used to the places of the industries where the waste materials and water passes to monitor the quality of the water in real time and proper authority can take legal action to prevent it. However, in this paper authors proposed to use this IoT based smart water monitoring service for the application of fish farming in Bangladesh. This IoT based whole system will help fish farmers to increase the quality and production of fishes. For the solution of the mentioned problem a IOT based device is proposed that have ability to sense the quality of the elements of the water such as dissolved oxygen, Nitrogen, pH ,water temperature, nitrite, ammonium, Co2, and it will be sent the measured data by sensors to a mobile via a mobile application.

Proposed device will be set into the water of any ponds, lakes or any source of water in the fisheries so that it can monitor the condition of the water in real time and the parameters will be sent to mobile app of the users. Users will be able to control the device through that mobile app and take treatment measure by observing the situation. There will be other advanced features integrated with the app. The IoT based sensor device will be movable so it can move every places in the water of pond, river or lakes to monitor the oxygen level and other parameters in water because the level of oxygen is not equal to all places in the water. Different fishes stay in the water at different level of water. By using the device user will get real time analysed information about the water and can easily take proper steps to make the water quality better so that fish can live there without facing any problems. Mobile app will have many features added for advance monitoring and action plan. This system will be very helpful for the fish farmers of our country and eventually country will be benefited by exporting fishes in abroad and earn foreign currency which will help to develop the economy of the country.