This answer depends on the wants and desires of the aquarium keeper. FSA&L aquarium services technicians believe both freshwater and saltwater/marine tropical fish tanks can be beautiful displays, and both offer colorful and interesting fish. Marine fish do have bolder brighter colors than their freshwater cousins but the choices are greatly limited, they are more difficult to maintain in an aquarium, and the prices are higher. Freshwater tropical fish also offer some very colorful and interesting fish but one may have to look a little harder to find the tropical fish sellers that carry those fish, which you will not find in the “Big Name” pet stores, and these fish may have a higher price range as well. The freshwater aquarium will allow the keeper to have a higher stock level in their tank, whereas marine aquariums should be relatively lightly stocked; for example a 100 gallon marine aquarium may house 10 medium size fish and a 100 gallon freshwater aquarium may house 30+ fish. Freshwater fish are largely bred in captivity and are accustomed to being kept in tanks, while their marine cousins are still largely harvested from the wild and may have a difficult time adjusting to their new environments. The captive bred marine fish are very limited in availability and carry an even higher price tag than wild caught marine fish. A marine aquarium, although there are exceptions to every rule, should generally be no smaller than 100 gallons; freshwater aquariums can start at as little as 30 gallons for a nice tank display. Regardless of the type of water in the tank, when aquarium maintenance is done correctly both can be decorative and make beautiful display tanks with interesting fishes. What type of tank to do depends on your particular interest and budget. Aquarium services, aquarium installations provided by FULL SERVICE AQUATICS will make aquarium maintenance in New Jersey simple no matter what type of aquarium you choose.