Abstract: A variety of marine ecosystems play important role in the ocean biological carbon sink. More and more often, people are paying closer attention to impacts of marine fish on carbon cycle. Recent studies showed that marine fish produce and excrete various form of precipitated calcium carbonate with high magnesium content from their guts. Precipitation occurs as a by-product of the osmoregulatory requirement of teleosts to continuously drink Ca- and Mg-rich seawater. Using the Bahamian archipelago site specific fish biomass and carbonate excretion rate data, scientists estimated that marine fish produce about 1.1×1012 kg CaCO3/year as mud-grade carbonate, and it is potential sediment constituent. Marine fish contribute over 14% to total estimated global carbonate mud production. Therefore, marine fish represent a hitherto unrecognized but significant source of fine-grained carbonate sediment, and affect coastal carbon sink capacity. This directly affect connotation of carbon sink fisheries. The carbon budget of marine fish culture may influence carbon source and carbon sink. Moreover, establishing the carbon budget model and their ability to trap carbon by cultured species is needed to produce realistic estimates for carbon sink value of marine fish culture.