Can I leave my Aquarium light on?

I'm a doctor and I have a giant gourami I've been having him for a very long time. He is housed in a 8ft by 3ft by 4ft(depth) with a custom built filtration coz he poops alot. That in place I had the aquarium designers to fix a good lighting. The aquarium is placed in my clinic where the patients get to see him. The aquarium looks simply stunning with the lights on. I prefer to leave in on throughout the day but I've noticed the water gets slightly warm near the surface. The tank holding the mive volume so heat is probably dissipated before it could reach the bottom. Is it ok? Can I leave the lights on throughout the day until I close my clinic at least(about 10pm). Thanks. btw if you're wondering about temperature control I'm in the Equator so this is the native area of the GIant Gourami they thrive in this climate/temperature - my aquarium designer said that I don't need a temperature regulator. The temperature here maintains about 27C(rainy season) to the maximum of 33C(hot season). Thanks again.