Can you tan a pleco?

[thefredpit]

I was watching King of DIY earlier and he was talking about using UVa and UVb tanning lights to bring out the red in asian arowana. This got me wondering if you could do this to bring out the red in some plecos like an L137? Here is an article I found describing how it works

https://aquamistglobal.com/2017/05/25/s ... r-arowana/

[Fundulopanchax76]

Plecos live hidden in their caves almost all the time ! They dont like light - its unnatural to them to be exposed to light ! This may cause them stress or maybe even death. So i dont think its good idea to expose them to UV rays.

[Bas Pels]

Further, UV will be adsorbed by water. I did not follow the link, but using UV for waterborne creatures is a waste of energy and thus money

[Linus_Cello]

Maybe feeding plecos with food rich in beta carotene may be more effective to bring out the reds.

I think I remember seeing plecos kept in outdoor tanks ( L14?) kept in the tropics, and they did seem richer in color. Maybe it was the sunlight, or maybe something else.

[thefredpit]

Plecos live hidden in their caves almost all the time ! They dont like light - its unnatural to them to be exposed to light ! This may cause them stress or maybe even death. So i dont think its good idea to expose them to UV rays.

I wasn't planning on actually doing this because of the stress it would cause I was just curious if it would have a similar effect.

[thefredpit]

Further, UV will be adsorbed by water. I did not follow the link, but using UV for waterborne creatures is a waste of energy and thus money

The link was saying that UV penetrates a couple feet of water but not glass so they actually make submersible UV lights. This practice is apparently something pretty common with red asian arowanas and this link explains the science of how it works

[TwoTankAmin]

Color me skeptical. I am not sure I would trust that article. I spent a little time looking into UVa and UVb rays and fish. Here is a quote from a CNN piece on sunlight:

Myth #3: Sun can't penetrate through windows.
Reality: Glass filters out only one kind of radiation -- UVB rays. But UVA rays, which penetrate deeper, can still get through. That's why many adults have more freckles on their left side than their right -- it's from UV exposure on that side through the car window when driving. To protect yourself, apply sunscreen to any exposed areas (like your hands, forearms, and face) before getting into your car, especially in the spring and summer months, says Anthony Mancini, M.D., head of pediatric dermatology at Children's Memorial Hospital in Chicago. If you're buying a new car, consider one with tinted windows, which keep out almost four times more UVA light than regular ones. You don't need to worry about putting on sunscreen when indoors unless you or your child spends most of your time near a window (for example, if your child's desk is right next to one).

from https://www.cnn.com/2012/07/10/living/g ... index.html

And here is what the aro link above states:

Always remember, the spectrum of sunlight we are concerned with tanning and scale color is UVa and UVb, and both these rays (rays of these wavelengths) DO NOT PASS through GLASS!

Clearly both these things cannot be true at the same time.

Next the aro link stated:

Arowana fishes are surface grazers, and are naturally found in black waters with lower acidic waters, since penetration of sunlight in these waters are perennial to first few feet, it does have a big role in an arowana’s scale shine intensity and color.

However, in a paper dealing with UVR and I found this:
UV radiation and freshwater zooplankton: damage, protection and recovery
Milla Rautio1,2,* and Barbara Tartarotti3

Coloured dissolved organic matter (CDOM) and UV attenuation in water

The UVR regime in the water column differs from that reaching the ground. The penetration of UVR wavelengths into water is highly dependent on the colour of the water, which is defined by the amount of coloured dissolved organic matter (CDOM) in water and is estimated from the concentration of dissolved organic carbon (DOC). Typically, half of lake water DOC is composed of coloured compounds and DOC can therefore be used to predict UVR transparency, except in the lowest CDOM environments such as in some alpine lakes (Laurion et al., 1997; Sommaruga, 2001; Sommaruga & Augustin, 2006) where particles may also play a significant role in UVR attenuation, and in ‘white DOC’ lakes such as in Greenland where highly UVR-transparent lakes may have very high concentrations of DOC (> 100 mgC L−1) (Anderson & Stedmon, 2007). The clearest lakes (< 2 mgC L−1) are usually found above the tree line (Morris et al., 1995; Vincent & Pienitz, 1996; Rautio & Korhola, 2002a) with UV-B penetration to several metres depth (Schindler et al., 1996), while some humic lakes can have DOC concentration > 30 mgC L−1 and the UVR is absorbed within the first few centimetres (Kirk, 1994) (Fig. 1). The darkest lakes can be considered well-protected from UVR, however UV-irradiated DOC may promote the formation of reactive oxygen species (ROS) that in turn are harmful to toxic to organisms including zooplankton (Souza et al., 2007).

from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079903/

This would suggest that in stained water UVR may barely penetrate down to a few feet and the paper says a few centimeters. Again, both things cannot be true at the same time. So if UVa and UVb dont penetrate well in stained water, how can they be what causes intense coloration of aros in the wild?

Since I do not keep aros I am in no way well informed about them. But the above and other articles I checked into suggest that the aro article linked may not be accurate. I am happy to be proved wrong, if that is the case.

[catfishchaos]

As stated I don’t think it would have an impact on bottom dwellers but I could see it having an effect on a topwater species like hatchets or aros. I would imagine the wet vs dry season would also effect the clarity of the water and thus the amount of uva and uvb rays that could penetrate and affect a fish. Interesting discussion though.

[b.reder]

TwoTankAmin -

That was a nice scholarly presentation. Thank you. -Barry

[thefredpit]

Color me skeptical. I am not sure I would trust that article. I spent a little time looking into UVa and UVb rays and fish. Here is a quote from a CNN piece on sunlight:

Myth #3: Sun can't penetrate through windows.
Reality: Glass filters out only one kind of radiation -- UVB rays. But UVA rays, which penetrate deeper, can still get through. That's why many adults have more freckles on their left side than their right -- it's from UV exposure on that side through the car window when driving. To protect yourself, apply sunscreen to any exposed areas (like your hands, forearms, and face) before getting into your car, especially in the spring and summer months, says Anthony Mancini, M.D., head of pediatric dermatology at Children's Memorial Hospital in Chicago. If you're buying a new car, consider one with tinted windows, which keep out almost four times more UVA light than regular ones. You don't need to worry about putting on sunscreen when indoors unless you or your child spends most of your time near a window (for example, if your child's desk is right next to one).

from https://www.cnn.com/2012/07/10/living/g ... index.html

And here is what the aro link above states:

Always remember, the spectrum of sunlight we are concerned with tanning and scale color is UVa and UVb, and both these rays (rays of these wavelengths) DO NOT PASS through GLASS!

Clearly both these things cannot be true at the same time.

Next the aro link stated:

Arowana fishes are surface grazers, and are naturally found in black waters with lower acidic waters, since penetration of sunlight in these waters are perennial to first few feet, it does have a big role in an arowana’s scale shine intensity and color.

However, in a paper dealing with UVR and I found this:
UV radiation and freshwater zooplankton: damage, protection and recovery
Milla Rautio1,2,* and Barbara Tartarotti3

Coloured dissolved organic matter (CDOM) and UV attenuation in water

The UVR regime in the water column differs from that reaching the ground. The penetration of UVR wavelengths into water is highly dependent on the colour of the water, which is defined by the amount of coloured dissolved organic matter (CDOM) in water and is estimated from the concentration of dissolved organic carbon (DOC). Typically, half of lake water DOC is composed of coloured compounds and DOC can therefore be used to predict UVR transparency, except in the lowest CDOM environments such as in some alpine lakes (Laurion et al., 1997; Sommaruga, 2001; Sommaruga & Augustin, 2006) where particles may also play a significant role in UVR attenuation, and in ‘white DOC’ lakes such as in Greenland where highly UVR-transparent lakes may have very high concentrations of DOC (> 100 mgC L−1) (Anderson & Stedmon, 2007). The clearest lakes (< 2 mgC L−1) are usually found above the tree line (Morris et al., 1995; Vincent & Pienitz, 1996; Rautio & Korhola, 2002a) with UV-B penetration to several metres depth (Schindler et al., 1996), while some humic lakes can have DOC concentration > 30 mgC L−1 and the UVR is absorbed within the first few centimetres (Kirk, 1994) (Fig. 1). The darkest lakes can be considered well-protected from UVR, however UV-irradiated DOC may promote the formation of reactive oxygen species (ROS) that in turn are harmful to toxic to organisms including zooplankton (Souza et al., 2007).

from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079903/

This would suggest that in stained water UVR may barely penetrate down to a few feet and the paper says a few centimeters. Again, both things cannot be true at the same time. So if UVa and UVb dont penetrate well in stained water, how can they be what causes intense coloration of aros in the wild?

Since I do not keep aros I am in no way well informed about them. But the above and other articles I checked into suggest that the aro article linked may not be accurate. I am happy to be proved wrong, if that is the case.

I chose that article by chance but tanning seems to be a common thing with show arowana. As to why tanning would affect arowana even with low penetration into water I believe this would be because arowana tend to hang out at the surface

[thefredpit]

As stated I don’t think it would have an impact on bottom dwellers but I could see it having an effect on a topwater species like hatchets or aros. I would imagine the wet vs dry season would also effect the clarity of the water and thus the amount of uva and uvb rays that could penetrate and affect a fish. Interesting discussion though.

I was sure it wouldn't have an affect on bottom dwellers in the wild but it peaked my interest on whether it might affect them if artificially done

[thefredpit]

TwoTankAmin -

That was a nice scholarly presentation. Thank you. -Barry

I agree good presentation TwoTankAmin