apt installed cudnn not persisting between terminaks

Installing nvidia cudnn with

sudo apt install nvidia-cudnn nvidia-cuda-toolkit

does not seem to persist some variables between shells and rebooting the PC: it workds fine on installation but on launching a new shell, if the program needs cudnn, it fails to find the shared libraries.

OS is Ubuntu 23.10 using fish as my primary shell

reinstallation works to fix this but seems suboptimal