To reproduce eels need to migrate over 6000 km and at pressure but before this migration they metamorphose into silver eels (silvering). The question raised in this study is to determine whether and how the silvering process contributes to pressure resistance. As migration represents a long swimming activity mainly performed with slow muscles, the red muscle energetics of pressure exposed silver eels was studied. By comparing these results to what has already been shown in yellow eels, we point out that the effects of the silvering process on pressure resistance are similar to the effects of pressure acclimatization in yellow eels. As previously shown, success of pressure acclimatization depends on membrane fluidity, but we raise the hypothesis that the high-pressure resistance of silver eels is due to more fluid membranes.