The addition of different types of accessories can help keep fish entertained. Colorful gravel, stones, arches and bridges that fish can swim through or over or under can keep fish busy. Place a colorful background picture at the back of the aquarium. You can find different scenes depending on what you want for your aquarium and they can be changed. There are treasure chests, dolls that look like divers or mermaids, all kinds of structures available to attrach your fish. Pet shops also have a variety of different plants that can add interest. And you can keep on adding depending on the size of your aquarium and/or redecorate when you like.