Can I leave the fish tank light on at night? There are pig-nosed turtles, golden dragons and silver dragons in it.

If the lights are not turned off all the time, it will affect the rest of the fish. Fish, like people, can't get enough rest after a long period of light, and it is easy to get sick after a long time. If you need to turn on the light for some special reasons, just open a small wattage nightlight near the fish tank.