It's very important as part of your plan for having successful aquarium to take note of the type of inhabitants. One of the most important elements of you aquarium will naturaly be fish. Never buy fish before finding out about its requirement first. You really need to take your time to ask questions and be very observant when you are in the aquarium store. There are lots of aquarium stores with unknowledgeable owners, so you don't base your decision on their advice alone... make sure you take a look at the fish yourself.