Why Use Red Light For Night Viewing?

[thefirethief]

This is out of curiosity. Can anyone give me a dumbed down scientific explanation about why, for viewing aquariums at night, red light is better than blue? I'll take a guess that natural moonlight sits mostly at the blue end of the spectrum therefore nocturnal marine life aren't sensitive or effectively blind and oblivious to red light. No? hmmm. I should trawl through google.

 

[xxBarneyxx]

The red spectrum of sunlight is effectively filtered out after a depth of about a meter so most marine animals can not see it. This is why there are quiet a lot of red marine animals as it makes effective camouflage.

 

[thefirethief]

Cheers for that Barney. I knew that clownfish, for example, will appear black at a certain depth but figured if red light was shone on them at any depth then predators would see them. I was actually wondering if the connection was something to do with how far red light penetrates the water. So its nothing to do with light reflection, its the fact that animals that don't normally experience light at the red end simply don't see it when it is there. Got yeee!

 

[Lynden]

My pep shrimp flee from red light, and my puffer becomes severely disoriented when subject to it. It got so bad that I switched to a white light for night viewing, though I still use the red one to scare him away from potentially dangerous or damaging situations.

 

[Filmoholic]

As soon as you use one you relize why too use it.Everything just goes as if your not there its pretty cool.

 

[xxBarneyxx]

Yeah I think in general most red animals can see red to a degree and some predators are specially adapted to see red.

 

[thefirethief]

I've been doing a bit of reading and it appears, as we guessed, that deep sea fish and inverts don't see red because they are only sensitive to the blue wavelengths available to them at those kind of depths. I guess red light will work in general however there will be some species of fish in the aquarium who live in shallower water and will have adapted to use red wavelength too.

My pep shrimp flee from red light, and my puffer becomes severely disoriented when subject to it.

Lynden, that might explain why your puffer gets disorientated as its my understanding most puffers available in to fishkeepers come from coastal shallow water.

 

[Lynden]

Yup. But so do many of the other creatures we keep.

 

[loachman]

The red spectrum of sunlight is effectively filtered out after a depth of about a meter so most marine animals can not see it. This is why there are quiet a lot of red marine animals as it makes effective camouflage.

Yup. Reds are absorbed heavily by saltwater so it's not overly useful to be able to see red (it only goes a couple feet).