Shrimp farming is a rapidly growing aquaculture practice, where maintaining optimal water quality is essential for healthy shrimp growth and improved productivity. Conventional water quality monitoring methods rely on manual testing and periodic sampling, which often fail to detect sudden changes in critical parameters, leading to stress, disease, and economic losses. This research presents an Internet of Things based real-time water purity monitoring and alert system for sustainable shrimp farming. The proposed system continuously monitors essential water parameters such as pH, temperature, salinity, and turbidity using integrated sensors connected to a microcontroller unit. The collected data is transmitted wirelessly to a cloud-based platform, enabling real-time visualization and remote monitoring. Predefined threshold values are used to analyse the water conditions, and instant alert notifications are generated whenever the parameters exceed safe limits, allowing timely corrective actions by farmers. Experimental evaluation of the system demonstrates improved monitoring accuracy, reduced response time, and effective detection of abnormal water conditions when compared to traditional monitoring techniques. The results indicate that the proposed system minimizes shrimp mortality, reduces labour dependency, and enhances overall farm efficiency. The low-cost, scalable, and energy-efficient design of the system makes it suitable for both small-scale and large-scale shrimp farms. This work concludes that the implementation of real-time monitoring and alert mechanisms significantly supports sustainable aquaculture practices and contributes to smart farming solutions.