Unless you purchased your home aquarium as an all-in-one kit which already has one, you will likely want to look into an aquarium hood for your set up. Even if you did get one in a kit, you may be interested in upgrading to a nicer style. The hood can serve several purposes for your aquarium set up.
First, the hood provides a finished look. It encloses the top of the aquarium so that items do not accidentally fall into the tank. Very often, the hood has a light source to illuminate the aquarium, providing simulated sunlight for aquarium plants and the fish, or just providing light in order to view the tank easier.
The hood also helps to keep the water from evaporating too rapidly by keeping the top covered and not exposed to the air. A hood will also help protect the water from air-borne contaminants and dust, some of which could be harmful to the fish. Also, a closed top will keep fish from leaping to a premature death, as some species are more prone than others to jumping out of the water; the hoods helps protect them and your investment in them.
When exploring hoods, you will consider the material that it is made out of. The simplest hoods are made from clear glass or plastic and simply cover the top of the tank. There is often two pieces to the hood connected by a plastic strip that serves as a hinge so you can lift one side to feed and clean the tank. With this set up you could rest a tube light on the non-moving side of the hood, but of course the parts are exposed and it does not have a finished look.
Wooden hoods can be quite elegant and made to match many decors. Wood and water often do not get along well together, so wooden hoods need to be treated to be water resistant. Plastic hoods are most common because they are durable and inexpensive.
When selecting a hood be sure to watch that it will fit your tank. Some hoods are designed to go on aquariums from certain companies and may not fit all models of tank.