Do not use brick walls which are made of concrete. It should be boiled in several changes of water and be immersed in water for several weeks before used in aquarium to kill any pathogens and make it sink. There should be no discoloration of water from tannins in the wood which lowers the pH and causes harm to fish. You can obtain wood safe to use from pet stores. Both the plastic and real plants can serve as decoration and hiding place for the fish.
Plastic plants are maintenance free.
Real plants can also help remove nitrate. There are wide variety of aquatic plants you can grow. Keeping one or two real plants does not require much work. However, if you are interested in serious underwater gardening, you have to consider special lighting requirements, etc. If you want to know more about serious underwater gardening, please come and talk to our staff.