Red or blue lights

[Dan Hudock]

Which light is better for seeing more nocturnal fish, blue or red?  I want to use it a couple of hours before I go to bed to see some of these fish.  I have a fully planted tank.

 

[Streetwise]

That is a really good question. Late night blue seems to be a thing, but maybe it is a holdover from marine tanks. In sailing, we prefer red lights for instruments and cabin lights at night because they don't wreck your night-vision. Various phones, tablets, and computers now have night modes which limit the blue light that keeps us awake.

I am tempted to change my Fluval programs to do 1% pink instead of 1% blue for the 21:00 - 22:00 phase of my schedule.

Edit: schedule changed. Sailing quote:

"Red sky at night: sailors' delight; red sky at morning: sailors take warning."

I'll report back on this.

Edited September 30, 2020 by Streetwise

[RyanR]

The only things I've heard is about blue lights.  The blue lights grow algae quickly and that plants don't "see" blue lights, so to plants it's like having the lights off.

[Streetwise]

The 1% pink just came on for my test. It looks weird.

Edit: I had to change it. I tried cold white, which was too bright. I think blue is the only option on these lights that has a low-enough brightness. There are different amounts of each color LED, plus whatever the software does.

Edited October 1, 2020 by Streetwise
Update

[Ben Ellison]

According  to what I've read in the past fish supposedly can't see red. So they suggest that red light means nocturnal fish are supposed  to think its dark. My lights don't support  a red mode so I haven't  actually  tested it.

[Dan Hudock]

10 hours ago, Streetwise said:

The 1% pink just came on for my test. It looks weird.

Edit: I had to change it. I tried cold white, which was too bright. I think blue is the only option on these lights that has a low-enough brightness. There are different amounts of each color LED, plus whatever the software does.

 

10 hours ago, Streetwise said:

The 1% pink just came on for my test. It looks weird.

Edit: I had to change it. I tried cold white, which was too bright. I think blue is the only option on these lights that has a low-enough brightness. There are different amounts of each color LED, plus whatever the software does.

OK, Thanks.  I tried it last night and agree with you... it looks weird.

 

[Streetwise]

It was like being in the Upside Down.

[Streetwise]

I've been thinking about this more since this thread was started. I actually ran with the cool white for a little while more, and then switched back to the blue, but I still wasn't enjoying that hour as much as I remember from when I first started. Then I realized that the six Plant Nanos in the room were all running in the tall configuration, and throwing a lot of ambient light around the room, compared to the long Fluval 3.0 on my Askoll 20 tank.

Last night, I changed the schedule of all the Nanos to not do a 1% hour at all. Now that I am just lighting one tank for that hour, and I can't see the LEDs, the night view hour is much more enjoyable again.

Now I am going to focus on hiding or dimming equipment lights, like the orange I get from my Apex, and lights from other bits of technology in the room.

Cheers

Edited October 8, 2020 by Streetwise

[Cory]

On 9/29/2020 at 8:07 PM, RyanR said:

The only things I've heard is about blue lights.  The blue lights grow algae quickly and that plants don't "see" blue lights, so to plants it's like having the lights off.

Just wanted to chime in here. Blue light doesn't grow algae any quicker than other light. Plants see Green the least, but our human eyes see green light the best. I'm not not sure what spectrums fish see the best/worst. Blue night lights "grow algae" because the light is on 24/7, the color it is doesn't really contribute to the algae grow, just the fact that algae is able to photosynthesize for 24 hours instead of a typical 8-12 hour period. Plants also can't really go past 14 hours, they have to rest where algae doesn't. 

[yannachka]

On 10/1/2020 at 1:12 AM, Ben Ellison said:

According  to what I've read in the past fish supposedly can't see red. So they suggest that red light means nocturnal fish are supposed  to think its dark. My lights don't support  a red mode so I haven't  actually  tested it.

i have read this as well, especially for catfish. i have my lights run red for an hour every night and it is the only time i see all of the cats and nocturnal fish come out so im personally inclined to believe it. the fluval 3.0s dont actually have red they have pink which does look weird. you get used to it after a while. the ai prime has a more true red.

 

[RyanR]

2 minutes ago, Cory said:

Just wanted to chime in here. Blue light doesn't grow algae any quicker than other light. Plants see Green the least, but our human eyes see green light the best. I'm not not sure what spectrums fish see the best/worst. Blue night lights "grow algae" because the light is on 24/7, the color it is doesn't really contribute to the algae grow, just the fact that algae is able to photosynthesize for 24 hours instead of a typical 8-12 hour period. Plants also can't really go past 14 hours, they have to rest where algae doesn't. 

Thanks for clarifying that @Cory.

[TomO]

Aside from keeping fish I also catch and eat my fair share. According to the fishing tackle companies, fish can't see red. That's why fish hooks are red, and there's even red fishing line. It's said to disappear at 3 1/2 feet in depth

[Daniel]

6 hours ago, TomO said:

Aside from keeping fish I also catch and eat my fair share. According to the fishing tackle companies, fish can't see red. That's why fish hooks are red, and there's even red fishing line. It's said to disappear at 3 1/2 feet in depth

That is an interesting point that got me thinking. I keep honey bees and they can't see red either. Honey bees can be trained to make choices for nectar rewards and they treat red and gray as the same color.

But @Taylor Blake and @WhitecloudDynasty keep and breed rainbow shiners and rainbow shiner males turn a vivid red while breeding. That implies at least some fish can see red.

After a little further Googling I found this Cornell professor who says Goldfish have cones in their retina for detecting red light.

Cornell Center for Materials Research - Do fish see in color?

WWW.CCMR.CORNELL.EDU

---

There is not just a single answer to this question since not all fish have been tested for color vision. However, the common goldfish certainly sees in...

He goes on to say that this doesn't mean goldfish can see red light, just that it needs to be tested.

Thanks @TomO for mentioning this, I love questions like this.

[Fishoutawater]

7 hours ago, TomO said:

Aside from keeping fish I also catch and eat my fair share. According to the fishing tackle companies, fish can't see red. That's why fish hooks are red, and there's even red fishing line. It's said to disappear at 3 1/2 feet in depth

thats funny in australia we routinely use red to attract fish to our baits.biggest one i can think of is red lures for redfin nothing else seems to have the same strike rate and putting little red beads above whiting or snapper  baits is common as well.an easy test would be to put some red food dye in some pellets and see if the fish find them easily still.could also test blue the same way.

[WhitecloudDynasty]

I also work with Greenhead shiner, in breeding mode they turn all red with all white fin. There have to be a reason they turn red over the other color. 

 

As for the red hook idea, I think its made red so it seem the bait is bleeding out.

[RyanR]

On 10/28/2020 at 10:28 PM, TomO said:

...According to the fishing tackle companies, fish can't see red. That's why fish hooks are red, and there's even red fishing line. It's said to disappear at 3 1/2 feet in depth.

I fish a lot, both along the Louisiana coast and in the Gulf of Mexico.  Any scuba diver will confirm this, but red is the first color to "disappear" from the color spectrum.  This is the reason some fish hooks are red.  I don't know the depth at which it can't be seen, but I would think that it depends on the clarity of the water and how far sunlight can penetrate the water.

[Streetwise]

I found a few articles online. One had this graphic: