Plankton is not the name of a plant or animal but more of a category for any drifting organism that inhabits the middle to upper levels of the ocean, namely the pelagic zone.
Most vets do spays, neuters, bone surgeries, spleen surgery, tumor removals, and intestinal surgeries. Heart surgery and more complicated surgeries are done by specialists that requires more schooling. If you want to be a vet, you have to have REALLY good grades and Vet school is MUCH harder to get into than human medical school.
Daily Tasks for Veterinarian Careers. Most of the small animal vet's work is conducted in the surgery, in consultation with owners. Vets typically have to treat all sorts of family pets. If you would like a veterinarian career specialising in birds or cats or dogs then this possible in larger practices.