There's lots of plants, such as ribbonweed, and other animals like shrimps and coral. These are good because they make the tank look pretty and can help remove waste food or give fish more places to hide.

Check with the aquarium shop that you're matching freshwater plants with freshwater fish and saltwater plants with saltwater fish.

You might also want to add other features like toy shipwrecks and dead coral These create hiding places for fish just as the real objects provide extra protection for fish in nature.