The utilization of carbohydrate in fish seems low compared with terrestrial animals,with intolerance to hyperglycemia,but the glucose regulation mechanism does exist in fish.In order to update the studies on glucosensing and carbohydrate metabolism in fish,and provide basic information for getting a better understanding about these physiological mechanisms,this review briefly introduced the progress of research on glucose sensing and its relationship with appetite,and the regulation of glucose metabolism in fish.The piscine glucose sensors were located in the different parts of the body,including central nervous system(CNS)and peripheral tissues.It is worth noting that both the glucose sensors and appestat are located in the hypothalamus,and they are also both regulated by some endocrine factors,such as leptin,ghrelin,cholecystokinin(CCK),neuropeptide Y(NPY),and so on.In mammals,the glucose sensing and appetite regulation were linked by AMP-activated protein kinase(AMPK)and mammalian target of rapamycin(mTOR)signaling pathways.Although this link has not been identified yet in fish,it was found that the energy state or some endocrine factors of fish were highly related with AMPK or mTOR phosphorylation levels.Probably this link was presumably similar to that in mammalian.In addition,the blood glucose levels of fish were regulated by some endocrine factors such as insulin,glucagon-like peptide-1(GLP-1),ghrelin,CCK,NPY,somatostatin(SS),etc.Besides,the glycometabolism and utilization in fish was aslo regulated by dietary nutrients including carbohydrate,lipid and protein.High-carbohydrate diet increased the activity and mRNA expression of glucose kinase(GK)in the liver of fish,and the glycolysis were also strengthened,even in the early development.Moreover,the hepatic gluconeogenesis in omnivorous species was inhibited by high-carbohydrate diet,but unaffected in carnivorous.Furthermore,High-fat diet promoted the glycolysis in some species,and the gluconeogenesis was also promoted both by high-fat and high-protein diets.However,there are still some questions that need further research.Finally,the development tendency and research hotspot in the carbohydrate metabolism of fish were discussed.For example,how the CNS integrate the nutritional,endocrine and other signals to regulate food intake in fish? what is the mechanism behind the differences between herbivorous,omnivorous and carnivorous species in glucose tolerance and the regulation of hepatic gluconeogenesis,etc.