working in a pet store and a marine biologist is closer than OWNING one.
Owning one involves a ton of thing, probbly the least being the knowledge of fish.
You have to have a strong financial background, business sense, marketing. Being a marin biologist you goto work and someone pays you...All you have to do is focus on your task, nothing else.
Owning a store you have to be involved in all the day to day financial including work laws and you would be the one paying employees and taxes, bills and such. IMO anyone can be a marine biologist with the proper training, but even with schooling, only a select very few will be a successful business owner..
A good ananlogy is like saying do i want a baby or a dog? HUGE difference!