Fish tank aquarium lighting is only for our use and pleasure. It is not necessary for the fish to have lighting. They tend to colour up a bit more and it is more aesthetically pleasing for us to have lighting in an aquarium however ambient room lighting would be more than enough for the tropical fish we keep.
So how long should this lighting be on for. I would advise this is down to personal preference and lifestyle. Much of decision could also be down to trial and error and what type of aquarium you have. If it is a planted aquarium then 10-12 hours is advisable however it also depends on the size of tank, quantity of plants and the like as to what the optimum duration of lighting is, not to mention the total amount and wattage of lighting you are using.
I run my lighting on rift valley tanks for 14 hours a day, from 9AM to 11PM, this is due to my lifestyle and when I like to see the lights on in the tank. A major factor in this is that I am actively trying to promote algae growth to ensure the type of fish I keep have plenty of algae to graze on during the day before feeding time in the evening.
Lighting period is an important factor in algae control as we’ve covered in more depth in our article on controlling algae growth in the home aquarium. It would be best to start with a smaller time period and gradually increase it so maybe begin with 8 hours of the lights being on and move it up form here. If you are finding the algae is getting out of control then reduce this slightly until you reach a happy medium.
The most important thing to ensure happens is that you have the lighting on a timer, whether this be through a full on control unit with LED lighting such as the TMC Aquaray lighting controller system or a simple timer switch plug.
In summary, around 10-12 hours is a good period to aim for however individual requirements will affect this and cause it to deviate from this duration slightly.