There are lots of excellent jobs involving fish! You could work as an aquaculturist, restoration ecologist, marine biologist, fisheries scientist, etc. I’ve done a lot of work enhancing and restoring fish habitat as an ecologist.
If you’re passionate and become good at it, you can get a job doing whatever you want. I suggest volunteering with an organization that does work with fish. Also, look up job postings through universities, state / federal government and the aquaculture industry. See what kind of duties these jobs have and what requirements they have. Then determine if any of that sounds fun to you. Reach out to a school that where you’d like to study and see if they can give you an idea of fish focused careers.