Dormitator latifrons is an amphidromous fish widely distributed in the Pacific slope from California to Peru. Although this species has a high potential for aquaculture, there is little information about the blood parameters of sex and growth stage. Eighty specimens of D. latifrons (40 males and 40 females in two growth stages) were used. They were placed in 1700 L tanks, one for each group, and fed with a feed for Tilapia diet with 35% protein and 8% fat. At the end of 30 days, blood samples were collected. Some blood parameters were determined (hematocrit, glucose, total protein, albumin, globulin, and A/G), and hematocrit percentage, glucose, albumins, and globulins presented significant differences between stages (P < 0.05). Total proteins showed differences only between males and females (P < 0.05). The hematocrit registered significant differences between stage and sex (P < 0.05). Differences between stages and sex may be related to a higher growth rate, differences in feed conversion, an increase in energy expenditure, and variations in hormonal levels. This study is the first to determine some blood parameters of D. latifrons under experimental aquaculture conditions concerning sex and growth stage.