The integration of Digital Twins (DTs) into aquaculture represents a transformative paradigm shift, facilitating real-time monitoring and optimization of fish farming operations. Leveraging Internet of Things (IoT) devices, DTs bridge the gap between virtual and physical environments, enabling remote access and management of farms while enhancing fundamental functionalities and architectural designs, tailored for intelligent fish farming. Precision Fish Farming (PFF) emerges as a comprehensive framework, integrating technology and automation to address present and future challenges in aquaculture. Serving as a collaborative platform for research and industry sectors, PFF facilitates the seamless alignment of technological advancements with practical aquaculture operations. Through the integration of big data within Artificial Intelligence of Things (AIoT) systems, smart systems are enabled, where processed data transforms into actionable information accessible to users. The architecture incorporates diverse IoT devices and sensors, including underwater RGB cameras, sonar cameras, and water quality sensors, to facilitate data collection from aquaculture sites. Advanced data analytics techniques, such as machine learning and data mining, are employed to extract insights and predict outcomes from large datasets. The results are formatted into visualizations for easy interpretation by farmers and stakeholders, facilitating informed decision-making. Cloud computing services play a pivotal role in managing interconnected devices and applications, offering tools for data storage, analytics, and support for IoT and AI services. Moreover, AI technologies integrated within DT frameworks enable real-time monitoring, predictive analytics, and scenario planning, revolutionizing aquaculture operations. Specific DT services, including fish feeding management, fish metric estimation, environment monitoring, and fish health monitoring, are elaborated upon, highlighting the comprehensive approach to optimizing aquaculture operations. In conclusion, integrating DTs with advanced technologies holds immense potential for enhancing efficiency, sustainability, and decision-making processes in aquaculture, paving the way for true digitization in the industry.