We investigated transcriptional and translational changes in rete mirabile tissue of European yellow and silver eels. We therefore analyzed the transcriptome as well as the proteome of rete capillaries of specimens of both developmental stages. The results clearly show the presence of a large number of membrane transport proteins in the transcriptome as well as in the proteome. ATP required to energize ion and metabolite transport can be generated in the aerobic metabolism. A high ROS defense capacity is established in rete endothelial cells, probably connected to the hyperbaric oxygen partial pressures, generated in the rete by back-diffusion of oxygen. Overall design: Using Illumina Sequencing to obtain RNA-Seq data and statistical Deseq analysis, the transcriptomes of European eel rete mirabile tissues of animals of different developmental stages were compared. Using LC-MS/MS and statistical analysis, the proteomes of European eel rete mirabile tissues of animals of different developmental stages were compared.