Lighting

[Lisalou84]

Hi, I am new to fish keeping and have recently set up a 75litre tropical tank, so far I have one pleco, some neon tetras and some male guppies. The tank I have has a white and blue light on. I’ve read changing the lighting often can stress the fish. But my question is, how and when should I use the lighting? The room my fish are in is quite dark in the day due to my partner working nights, so not much daylight is let in, so what I’ve done so far is when I’m up in mornings I put the white light on for them to mimic daytime, I then switch the white light to the blue light once it’s dark outside, I then leave this on for around 5-6 hours I then turn all lights out so they have darkness throughout the night. I really want to get the settings right for my fish I really don’t want to stress them. So I’m asking if people think what I’m doing with the lighting is ok and safe for all my fish.
Thank you in advance

 

[Essjay]

The room light should be on or the room in daylight for at least half an hour before the tank lights turn on and at least half an hour after the tank lights turn off. Going from darkness to tank lights on and tank lights on to total darkness is stressful for fish. They need a period of "dawn and dusk" (the room light or natural light) for their eyes to adjust.
And the tank light should be on at the same time of day every day for the same length of time every day. A timer is the easiest way to do this.

I would leave the tank light on white only; blue encourages algae. I don't know why manufacturers insist on having white and blue leds in their lights. I had one where the only options were white & blue or just blue.

 

[Byron]

Agree with essjay. It also is important to have the light on the same schedule each day. All of this is covered in my article on light and how it affects fish, over on our member @AbbeysDad blog site, here is the link to the article:

Lighting: How It Affects Freshwater Fish – MJV Aquatics

mjvaquatics.com

 

[Uberhoust]

Two major reasons for the Blue LEDs

1. They are used for glow fish and florescent aquarium features and decorations.
2. They are used to change the color temperature for the light. A number of white LEDs are closer to the 3500k to 5500k, with the addition of the blue they can state the color temperature is 6000k to 7000k which is more appropriate for some plant communities. I believe this to be a miss use of color temperature because the color spectra follows a specific curve for a specific temperature and there are no discrete light frequencies.

Just my opinion from researching a number of LED light for my aquariums. I use the blue lights on my Nicrew G2 at 80% while the whites are at 100%. I only run the blues when the whites are also on.

 

[Colin_T]

If you want the fish to be awake when your partner is awake, have their tank light come on when they are awake. Just get a timer and have the lights come on the same time each day.

If you don't have any live plants in the tank, then you only need the light on for a few hours in the evening.

If you do have live plants in the tank, they need at least 8 hours of light per day, and you can have the lights on for up to 16 hours per day maximum. But most people have the light on for 10-12 hours a day and add or reduce time depending on how the plants do.