The spotted knifejaw (Oplegnathus punctatus) is a commercially valuable marine fish widely farmed in coastal areas of China, highly valued for its excellent flesh quality and high nutritional value. As one of the key species for offshore and deep-sea aquaculture in China, it has been demonstrated and promoted in large-scale aquaculture systems such as deep-water cages and engineered enclosures via a land-sea relay model. In aquatic ecosystems, this species frequently faces starvation stress due to natural factors such as seasonal changes and heterogeneous nutrient distribution, as well as aquaculture-related factors including uneven feed distribution caused by high stocking density and strategic fasting implemented for disease prevention and control. This stress disrupts energy metabolism, digestive function, and immune defense, thereby impairing the growth and survival of this species—two critical factors are key factors for sustainable aquaculture. However, research on the physiological responses of the spotted knifejaw to starvation and refeeding remains limited, which impedes the development of precise feeding strategies for its intensive farming. Given this, the present study conducted an experiment using 210 healthy spotted knifejaws (initial weight: 25.83±0.92 g; initial body length: 9.04±1.18 cm) , which were acclimatized for 7 days under controlled environmental conditions (temperature: 25±0.5℃; dissolved oxygen: ≥7.2 mg/L; pH: 8.0±0.2; ammonia nitrogen: ≤0.05 mg/L). The fish were then randomly divided into 7 groups (30 fish per group, with 3 biological replicates per group), with 30 fish per group and 3 replicates per group: 1 control group (S0) with continuous feeding, 4 starvation groups (S1, S5, S10, S15) with 1, 5, 10, and 15 days of fasting respectively, and 2 refeeding groups (R5, R10) subjected to 15 days of starvation followed by 5 or 10 days of refeeding. The experimental?assays and?methods were as follows: An automatic hematology analyzer (BC-2800vet) was used to determine. Commercial assay kits (Nanjing Jiancheng Bioengineering Institute, Nanjing, China) were used to measure plasma glucose content (glucose oxidase method), as well as hepatic glycogen and muscle glycogen contents (colorimetric method); intestinal digestive enzyme activities were assayed via: intestinal amylase (starch-iodine colorimetric method), intestinal lipase (colorimetric method), and intestinal chymotrypsin (colorimetric method).; Intestinal tissues were fixed in 4% paraformaldehyde, sectioned, and stained with HE, after which villus height (VH), villus width (VW), and muscular layer thickness (MT) were measured using ImageJ 1.8 software. Data were statistically analyzed using one-way analysis of variance (ANOVA), with the significance level set at P < 0.05. Results showed distinct glycogen metabolism patterns. Hepatic glycogen and blood glucose levels decreased significantly in S5 compared to S0 (P<0.05), reaching minimum levels in S15 with reductions of 68% and 54% respectively relative to S0, but partially recovered after refeeding with R10 being closer to S0. Muscle glycogen levels remained relatively stable, except that muscle glycogen in S15 was significantly lower than that in the S0 group (P<0.05). Intestinal digestive enzyme activities exhibited distinct trends: overall, intestinal lipase and chymotrypsin activities decreased with prolonged starvation; intestinal amylase activity in S5 was significantly higher than that in S0 (P < 0.05), followed by a?steady decrease in subsequent groups. Digestive enzyme activities in the R5 and R10 groups were higher than those in the S15 group, but the differences were not statistically significant (P>0.05). Blood physiological indices exhibited specific changes: White blood cell (WBC) counts showed an increasing trend during starvation and continued to rise after refeeding, with R10?exhibiting?significantly higher?WBC counts?than all starvation groups(P<0.05). Red blood cell (RBC) counts in R5 were significantly higher than those in S1 (P<0.05). Hemoglobin (Hb) levels in S15 were significantly higher than those in S1 (P<0.05). Intestinal tissue structure was progressively impaired: Muscular layer thickness in S10, villus width in S10, and villus height in S15 were all significantly lower than those in S0 (P<0.05), with villus height in S15 reduced by 11.1% compared to S0. This structural impairment was reversible after refeeding, and 10 days of refeeding was more effective than 5 days. In conclusion, short-term starvation stress (5 days) significantly increased intestinal amylase activity and decreased hepatic glycogen and blood glucose levels in the spotted knifejaw, while muscle glycogen levels remained stable. When starvation duration reached 10 days, it resulted in reduced activities of intestinal lipase and chymotrypsin, further decreased hepatic glycogen and blood glucose levels, increased white blood cell counts, and obvious intestinal structural damage Therefore, it is recommended that the maximum starvation duration for the spotted knifejaw in aquaculture production practices should not exceed 10 days. This study provides a scientific basis for formulating precise feeding strategies in the intensive aquaculture of the spotted knifejaw and contributes to understanding the physiological adaptation mechanisms of the spotted knifejaw to starvation stress.