Abstract: Carbon neutrality is the necessary path to cope with climate change. Marine negative emissions are an important way to achieve carbon neutrality. As the largest carbon reservoir on the earth, the ocean and coastal zone have been extensively studied as carbon sinks with the participations of various marine organisms. However, the role of fish, one of the most important components of marine ecosystems in carbon cycling has not received sufficient attention. Recent studies show that marine fish play an important role in the inorganic carbon cycle. A deeper understanding of the involvement of fish in the carbon cycle and quantifying their carbon sequestration potential can improve our understanding of ocean carbon cycling. In this paper, firstly we systematically review the progress of research on the process and mechanisms of fish involvement in carbon cycling. Fish participate in ocean carbon cycling through various pathways, including carbonate fecal production, horizontal and vertical migration and transport, bioturbation, biological and carcass carbon, and food web consumption and transfer. The evidence of fish involvement in carbon cycling and the importance of their roles become evident. Secondly, we presented the existing problems and challenges in the studies, including the debate on fishery source and sink, opportunities and challenges for aquaculture, and difficulties in accurately quantifying fish-derived carbonate. These issues require further theoretical and methodological studies as well as technological innovation to address. Finally, we propose the research prospects of fish involvement in carbon cycling and its potential opportunities in the context of global climate change. Based on the current development process and demand of fishery carbon sequestration, we provide suggestions for the development path of fishery emission reduction and carbon sequestration. We hope the studies can enhance understanding of the contribution of fish to ocean carbon cycling and their potential to serve ecosystems, providing new perspectives for ocean carbon and fishery carbon sequestration research.