Tropical Fish and Aquarium Rentals business. This is a colorful business idea for fish aficionados. Business Overview You can earn gigantic profits by starting a tropical fish and aquarium rental business, and best of all, this very unique enterprise can be set in motion for less than $5,000 and managed right from a homebased office. At this point, I am sure you're wondering exactly who would rent tropical fish and an aquarium? The list is very long, and if you think about...