Becoming an aquarium maintenance professional requires a broad base of knowledge ranging from biology to chemistry to equipment maintenance.  You need to know how to set up and stock both freshwater and saltwater aquariums, keep their inhabitants healthy, monitor water quality, and keep equipment purring away smoothly.  As you might guess, because of the equipment involved it can be a physically demanding career.  Fortunately, you do not need to earn a bachelor’s degree or even an associate’s degree to enter the profession.  You can prepare for an aquarium maintenance career by enrolling in a certification course that takes about eight months to complete.