Large and small aquariums can be decorated in a number of styles and themes, creating a fun view for you and a stimulating environment for your fish. Aquarium themes can range from the completely natural to the campy, using plants, figurines, coloured rocks and more.
About aquarium decorations
According to First Tank Guide, fish are more comfortable in aquariums that closely mimic their natural habitats, particularly those that include places to hide from predators. Fish that know they have protection around them are more likely to stay healthy and to swim more freely in the tank. Keep this in mind as you plan your aquarium's decor, so that you include several pieces that are larger than your fish and make good hiding places. About half of the aquarium should be filled with decorations. Always use decorations manufactured or grown specifically for aquariums; items not made for tank use could contain paints and other substances that could harm your fish.
Your fish won't care what the decorations are, as long as they have some, so you can go wild with your ideas. For fun aquarium scenes, you can replicate shipwrecks, include chests of sunken treasure and figurines to create a pirate theme, or build a forgotten underwater city with columns, ruins and buildings. Fantasy world decorations are also popular, such as sets of mermaid figurines, Poseidon and elaborate castles. If you like the idea of a deep-sea dive environment, there are models of shark skeletons and underwater volcanoes available.
Some aquarium owners prefer a more natural look for their tanks. Driftwood, both natural and artificial, comes in many sizes and provide good cover for fish. Replicas of coral and coral reef structures are also decorations that allow fish plenty of places to hide and swim inside. Aquarium rocks and caves are designed to look like naturally-occurring rock formations and add landscaping interest to an aquarium. Plastic plants are useful in both natural and themed aquariums, helping blur the lines of ceramic pieces.