I'll give you a bit of advice that not everyone will agree with but I aim it at the main mistake most beginners make. The ocean is a desert. It contains hundreds if not thousands of gallons of water for every fish. Research any fish you plan on buying to see how big it gets in nature. You don't want fish that need a hundred plus gallon tank to have swimming room and you don't want to place more fish in your tank than the equipment can support. A lot of the tanks on the internet that have large populations of fish usually have an even larger volume of water running in sumps, fuges, etc. doubling or tripling the amount of water in the system. Try to stock with a minimum of fish, testing the water quality at least weekly and you'll be able to judge what your system can safely support over time. No one can tell you how many fish to place in your tank. That depends on tank size, equipment, maintenance, choice of fish, other bio loads in the tank, amount of food added. Think of each fish a a little ammonia generator. More fish, more ammonia. Ultimately more nitrates that you have to remove from the system by water changes, harvesting macros, chemical removers. Enjoy the learning experience from your tank.
