Just to protect the fish and other animals that would become weak and fragile in presence of heat, some lights have a fan. Another thing you need to know is that these lights are durable. They could last for a couple of years and this is because most of them are made of coated aluminum. This means that these illuminators would never rust and thus, would remain shiny and lovely. In addition, the t5 aquarium light possesses high quality craftsmanship that guarantees high efficiency and safety.