Fish And The Visable Light Spectrum

[The-Wolf]

forgive me, my head hurts from thinking too much

ok
I saw these at a lfs
and they come in lots of colours (not just the what's in link).
White, red, orange, blue and green.
now the red pack specificaly states "for viewing nocturnal fish"

I have been under the impression that it's the blue end of the spectrum that fish can't see,
this is why moon lights are blue. I've also been under the impression that fish can see infared too.
I remember being told early on not to point the TV remote at the tank as it can affect the fish.

So have I go it wrong all this time, or has Hagen?

for those that are interested in the price
it was £19.99 for the start kit and around £10 for each additional light.

 

[fozzy_wozzy_woo]

Hagen is wrong. your right ...Blue light is more invisable to fish than red.. red is better for us as we have more blood running in the eyes than fish.

the red from the light goin into our eyes is made invisable because we are use to it.

There are forms of infr red that we can see.

If you go to a ministers house at night you will normally see two redlights on the top of a pole beside a small box.

This isnt for helicopters. these are high powered infra red spot lights. for the infra red camera that is in the little box beside it.

 

[Jules H-T]

Totally off topic, but digital cameras (including speed cameras) can see IR too. Switch on your camera phone and zap the remote into it to see what i mean.

 

[carrera]

Totally off topic, but digital cameras (including speed cameras) can see IR too. Switch on your camera phone and zap the remote into it to see what i mean.

ooh cooool

 

[gayno]

Jules is right you know!!

 

[Bignose]

The question of what light is absorbed the best really depends a lot on the fish's habitat and lifestyle.

"Morphology and spectral sensitivities of retinal and extraretinal
photoreceptors in freshwater teleosts" by C. Kusmic and P. Gualtieri in Micron volume 31, p. 183-200, 2000, has a chart that shows where in the light spectrum the different absorbancy maximas are. THe chart lists like 30 species, but are broken into 4 groups:

Group 1 are strictly diurnal species that live just below the water surface or live in shallow water. Some of the species listed are the guppies and swordtails. They have maximas in the violet part of the spectrum, right at 410-415 nm, and some in the blue part 460 nm. So, these fish should be very good at picking up blue light.

Group 2 are midwater swimmers, like barbs. Most of them don't have the violet peak, but the blue peak is present in almost every species this paper looked at.

Group 3 are nocturnal species, mostly predators. Group 4 are also nocturnal bottom dweelers, like cory catfish or red tailed black sharks. These do not have the violet or blue maximas at all, only the red ones.

However, it is obvious that like a lot of life, no one blanket statement can be said about all fish, depending upon their habitat and activities, the way they detect light varies.

 

[fozzy_wozzy_woo]

The question of what light is absorbed the best really depends a lot on the fish's habitat and lifestyle.

"Morphology and spectral sensitivities of retinal and extraretinal
photoreceptors in freshwater teleosts" by C. Kusmic and P. Gualtieri in Micron volume 31, p. 183-200, 2000, has a chart that shows where in the light spectrum the different absorbancy maximas are. THe chart lists like 30 species, but are broken into 4 groups:

Group 1 are strictly diurnal species that live just below the water surface or live in shallow water. Some of the species listed are the guppies and swordtails. They have maximas in the violet part of the spectrum, right at 410-415 nm, and some in the blue part 460 nm. So, these fish should be very good at picking up blue light.

Group 2 are midwater swimmers, like barbs. Most of them don't have the violet peak, but the blue peak is present in almost every species this paper looked at.

Group 3 are nocturnal species, mostly predators. Group 4 are also nocturnal bottom dweelers, like cory catfish or red tailed black sharks. These do not have the violet or blue maximas at all, only the red ones.

However, it is obvious that like a lot of life, no one blanket statement can be said about all fish, depending upon their habitat and activities, the way they detect light varies.

So basicly your saying is
group 1 can only see a littly blue light
Group 2 Cant see red but can see blue light
groups 3 and 4 can only see red light

Is this right??


if this is so then you could mix blue and red led bulbs in the tanks and this would then make it butter for the fish to see inthe dark

 

[Bignose]

I doubt that 'only' is the right word. The maximas are the wavelengths the fish see best, but the curves are rather Gaussian (a.k.a. normal) which means that there is significant reception around the peaks. How wide the peaks are is surely species dependent, but another graph in the above paper which shows just one species' entire curve (not just the maxima) shows that there is significant overlap. That is, the curves are wide enough that there is significant reception from UV to IR. The groups 3 and 4 probably have diminished blue reception, but non-zero. Maybe zero UV compared with the other species.

 

[annka5]

Ha hah! I never ever thought I'd be able to say this, but myLFS is cheaper! Sells them for £12 or £7 for the bulbs. I know, am petty, but you have to take your joys where you can....!
Have you tried them? On the instructions I think it says if you put them in the water then you get diffuse olight, above the water you get a beam. D'you reckon they would be enought to light a v small tank with only java-fern-on-a-rock in the way of plants? Am thinking of setting up a little tank for a betta or some shellies for the bedroom (have the tank, nothing else though)