The frequency of hypoxic events (i.e. decrease of dissolved oxygen level in water) is increasing at an unprecedented rate due to anthropogenic pollution and climate change. As species might not be able to adapt fast enough to this rapid change, they would need to rely on faster phenotypic responses such as plasticity. If the stressor becomes persistent, some transgenerational plasticity could occur. Physiologically the low oxygen environment can impact the organism's metabolism, potentially affecting their fitness. Therefore, more studies are needed to decipher fish metabolisms plasticity to hypoxia within and across generations. To investigate this, we did a multigenerational experiment with a wild population of Gasterosteus aculeatus. The first generation (F1) was either exposed to normoxia (100% dissolved oxygen, DO), or daily fluctuating hypoxia (30% DO at night and 100% DO during the day) mimicking the oxygen fluctuation happening in the wild. Their offspring (F2) were reared either matching their parental condition or not, resulting in four different groups reflecting within- or trans-generational plasticity. We assessed their aerobic metabolism (aerobic scope) and oxygen transport capacity (maximal heart rate frequency, blood hematocrit, and hemoglobin content) as well as the anaerobic metabolism (hypoxia tolerance and Pcrit). The results only showed within plasticity to fluctuating hypoxia with an increased hypoxia tolerance of the fish and decreased Pcrit, while the aerobic metabolism and oxygen transport capacity did not change. This study shows that fish might cope with this level of hypoxia through within-generation plasticity while transgenerational plasticity is not yet observed in measured traits.