This study investigated the use of eugenol or salt to mitigate stress in juvenile Lophiosilurus alexandri during transport in plastic bags. Juvenile L. alexandri (15.2 ± 3.8 g) were fasted for 24 h before transport. Experiment I tested four eugenol concentrations (0, 2.0, 4.0 and 6.0 mg L−1) with four replicates each, while Experiment II tested five salt concentrations (0, 2.0, 4.0, 6.0 and 8.0 g of salt L−1), with three replicates each. In both experiments, fish were stocked in plastic bags (10 animals per bag) containing eight liters of water with the concentration of eugenol or salt of the corresponding treatment. The bags were inflated with pure oxygen and sealed with a rubber band. Fish were transported for three hours, but the total time the fish were in the bags, from closing to opening, was five and a half hours. Survival was monitored and blood samples collected before transport (BT), immediately after transport (IAT), and at 24 and 48 h post-transport. No mortality was observed throughout the experimental period. All transported fish had significantly higher plasma glucose concentrations IAT than BT. The highest concentrations of eugenol (4 and 6 mg L−1) promoted decreased blood glucose levels 24 h after transport compared to the 0 mg L−1 control. Fish in all treatments using salt, as well as the control, had plasma glucose levels at 48 h that were similar to levels BT. Observed plasma protein levels were similar in both experiments. Hematocrit for all fish exposed to eugenol, as well as the control, were lower IAT than BT. Fish subjected to transport with the highest salt concentrations (6 and 8 g L−1) in the water exhibited a lower hematocrit IAT when compared to BT. However, this variable increased after 24 h of transport, similar to the BT group. The use of eugenol or salt in water during transport of juvenile L. alexandri in plastic bags was not effective in mitigating stress.