Your fish need to experience a day and night cycle, just like any other animal. Here are a few tips on how to adjust your aquarium lighting from day to night so that your fish remain healthy and happy in their environment.
If you’re reading anything about lighting for fish, it’s likely you’re reading about daytime lighting—how to illuminate your aquarium with LED, halide, or other type of lighting. There are two ways to adjust the lighting from day to night. One is just switching off the lights every evening. However, this is a little sudden and could cause some confusion in your fish. Many lights have dimmers built in and you could dim the light for twilight hours before switching off.
An easier way would be to have automated lighting. This can run the dimming cycle before it switches over to nighttime mode. Think sunsets and sunrises for the fish.
You could simply have the lights off during the nighttime, but trending now is LED lunar lights to simulate the wavelengths of real moonlight. These trigger natural biological activities in both your diurnal and nocturnal creatures.
What part of the globe your fish hail from will determine how long you need to keep the “daylight” lighting on. Most tropical fish have a steady year-round daytime cycle of anywhere form 11-13 hours. Your aquarium lighting should be timed carefully to respond to the ambient light in the room, which may mean lighting a little longer during those winter periods when the sun sets by 5pm.
If you have fresh water fish from a northern region, your lighting can better match your day. Shorter periods during the winter months and longer in the summer shouldn’t affect the behavior of the fish.
It is imperative you give your fish and coral a normal day and night cycle. Experiment with the length of cycles to find out what works for you and your fish.