Are Lights Necesary

[Bignose]

rdd, puff, you guys are wrong. Fish do need light, it is essential for their long-term health. Just like people, fish need Vitamin D, and also just like people, most of their Vitamin D is self-made, and light is a key part of the synthesis of Vitamin D. It is produced photochemically in the skin.

Vitamin D is very important, it helps regulate the calcium and phosphorus levels in the blood by promoting their adsorption through food through the intestines. Vitamin D also promotes bone formation and is essential in keeping bones strong -- if you don't get enough Vitamin D people get a disease known as rickets. I don't know what fish-rickets are, but I do know it cannot be good.

So, in summary, fish do have to get significant light. They need the light to make sure that they are getting their essential vitamins.

Fish dont synthesize Vitamin D in their skin using sunlight as humans do, Fish get their entire vitamin D content from their food. Most of the fish's Vitamin D will start off in aquatic plants or algae or phytoplankton etc and work its way through to the fish. Hence cave dwellers, black water fish and deep sea fish do just fine despite low or zero light levels. I wouldnt suggest keeping fish in zero light levels long term - many fish do use their eyes to see... but many fish do appreciate darker aquariums. Ive found that very dark aquariums are ideal for hospital tanks the VERY LOW light levels seem to lower stress levels in many species, particularly in blackwater \ deep water species species

Dang, someone really should have told Dr. Holick this when he wrote "and most plants and animals that are exposed to sunlight have the capacity to make vitamin D" in "Vitamin D: A millennium perspective" Journal of Cellular Biochemistry 2002. Someone else should have told that to Dr. Haussler when he wrote about fish's production of Vitamin D in "Vitamin D Receptors: Nature and Function" in Annual Review of Nutrition 1986. These are just two I found, that say that fish do produce Vitamin D in their skins. I am sure that Vitamin D is also a part of their natural diet, too, since almost all plants and animals make it when exposed to sunlight, but, a fish's own production is a significant part of its Vitamin D, too. Can you cite me some proof that shows that fish don't make their own? I'd very much like to take a look at it.

 

[Tolak]

I was under this impression as well.

 

[rdd1952]

That algae in the other post looks like hair algae but it's hard to tell.

I had not seen the other thread but in it you mentioned that you had 2 CAEs. They eat about as much algae as I do. They will eat it only as a very last resort. I can't remember if you posted the type fish you have or not but CAEs get very agressive as they get older and larger (6" or more) and will attack other fish, especially slow moving ones, and try to suck the slime coat off them. Flat bodied fish like angels and gouramis should definitely not be kept with CAEs. Corys are also at risk as they will eat the eyes out of corys.

 

[Davidtq]

rdd, puff, you guys are wrong. Fish do need light, it is essential for their long-term health. Just like people, fish need Vitamin D, and also just like people, most of their Vitamin D is self-made, and light is a key part of the synthesis of Vitamin D. It is produced photochemically in the skin.

Vitamin D is very important, it helps regulate the calcium and phosphorus levels in the blood by promoting their adsorption through food through the intestines. Vitamin D also promotes bone formation and is essential in keeping bones strong -- if you don't get enough Vitamin D people get a disease known as rickets. I don't know what fish-rickets are, but I do know it cannot be good.

So, in summary, fish do have to get significant light. They need the light to make sure that they are getting their essential vitamins.

Fish dont synthesize Vitamin D in their skin using sunlight as humans do, Fish get their entire vitamin D content from their food. Most of the fish's Vitamin D will start off in aquatic plants or algae or phytoplankton etc and work its way through to the fish. Hence cave dwellers, black water fish and deep sea fish do just fine despite low or zero light levels. I wouldnt suggest keeping fish in zero light levels long term - many fish do use their eyes to see... but many fish do appreciate darker aquariums. Ive found that very dark aquariums are ideal for hospital tanks the VERY LOW light levels seem to lower stress levels in many species, particularly in blackwater \ deep water species species

Dang, someone really should have told Dr. Holick this when he wrote "and most plants and animals that are exposed to sunlight have the capacity to make vitamin D" in "Vitamin D: A millennium perspective" Journal of Cellular Biochemistry 2002. Someone else should have told that to Dr. Haussler when he wrote about fish's production of Vitamin D in "Vitamin D Receptors: Nature and Function" in Annual Review of Nutrition 1986. These are just two I found, that say that fish do produce Vitamin D in their skins. I am sure that Vitamin D is also a part of their natural diet, too, since almost all plants and animals make it when exposed to sunlight, but, a fish's own production is a significant part of its Vitamin D, too. Can you cite me some proof that shows that fish don't make their own? I'd very much like to take a look at it.

http/www.ncbi.nlm.nih.gov/sites/entrez?c...p;dopt=Abstract

http/www.doctoryourself.com/dvitamin.htm

http/www.educacion.uanl.mx/publicaciones.../pdf/9Shiau.pdf

http/books.nap.edu/openbook.php?record_id=2115&page=25

Fish REQUIRE vitamin D in their diet they CANNOT synthesize vitamin D in sufficient quantites to survive without a vitamin D rich diet. This hardly surprising given the ability of water to reduce the levels of UV light required for synthesis of vitamin D and the quantities of Vitamin D available to fish in their natural diet, why would a fish adapt an ability to synthesize large amounts of vitamin D when they are surrounded by a vitamin D rich banquet?

Just how much UVB light does a normal aquarium light put out and how much of that gets filtered out by condensation trays and water? Why do manufacturers of fish food ensure that it contains Vitamin D?

 

[andywg]

Let's see some of those links

http/www.ncbi.nlm.nih.gov/sites/entrez?c...p;dopt=Abstract

This seems at odds with the two published papers bignose quoted. One would have to observe the peer review and more than just the abstract to establish what is most correct.

http/www.doctoryourself.com/dvitamin.htm

The above link states fish cannot produce Vitamin D, but does not reference it to any source, so it is an unsubstantiated claim. Considering Bignose has quoted from peer reviewed research, this can be effectively discounted.

http/www.educacion.uanl.mx/publicaciones.../pdf/9Shiau.pdf

The above states that the requirement in food for O. niloticus x O. aureus is 0.00937 mg kg-1 diet. a truly small amount. For O. aureus Vitamin D is stated as dispensable from the diet. If it is dispensible that means it is getting it from elsewhere. The skin, perhaps?

http/books.nap.edu/openbook.php?record_id=2115&page=25

Fish REQUIRE vitamin D in their diet they CANNOT synthesize vitamin D in sufficient quantites to survive without a vitamin D rich diet.

One of your own links appears to disprove this when discussing the vitamin requirements of tilapia. Indeed "O' Connell and Gatlin (1994) reported that dietry vitamin D3 is not dietry essential for O. aureus." (Effects of dietry calcium and vitamin D3 on weight gain and mineral composition of the blue tilapia (Oreochromis aureus) in low-calcium water Aquaculture 125, 105-117)

I believe bignose is correct when he states that the fish get vitamin D from both their diet and sunlight.

 

[Davidtq]

Let's see some of those links


One of your own links appears to disprove this when discussing the vitamin requirements of tilapia. Indeed "O' Connell and Gatlin (1994) reported that dietry vitamin D3 is not dietry essential for O. aureus." (Effects of dietry calcium and vitamin D3 on weight gain and mineral composition of the blue tilapia (Oreochromis aureus) in low-calcium water Aquaculture 125, 105-117)

I believe bignose is correct when he states that the fish get vitamin D from both their diet and sunlight.

The full title of the article by o'connell and gatlin is ". Effects of dietary calcium and vitamin D3 on weight gain and mineral composition of the blue tilapia (Oreochromis aureus) in low-calcium water"

Im having trouble finding the original article text, but I would imagine that its very possible that in specific low calcium environments more vitamin D has no effect at all, If lack of calcium is the growth limiting factor then lower amounts of vitamin D are required for what growth does happen, It would be interesting to see the actual articles from which the quotes about dietry requirements of fish for Vitamin D are pulled. Everywhere I can find lists vitamin D as a dietry requirement which would suggest the fish in question cannot synthesize enough vitamin D themselves.

Another article http/books.google.com/books?id=GhHg7npYIKsC&pg=PA63&lpg=PA63&dq=channel+catfish+dietry+vitamin+d+requirements&source=web&ots=Wvx3EwrvCK&sig=ibxgU7r9Hv2WzICxLh4GZUYum50#PPA64,M1

"some vitamins, such as vitamin D,K,B12 and choline are apparantly required at low levels or their requirements are impacted by other chemicals or organisms. While it has been difficult to demonstrate a requirement for Vitamin D deficiency signs including reduced weight gain poor food conversion efficiency and an effect on bone mineralisation have been observed when extremely low levels of the vitamin are fed (lovell and li 1978, andrews et al 1980)."

What I have yet to see is ANY figures on vitamin D synthesis in fish, any figures suggesting how much of their requirements they can gain from exposure to UVb (which is very limited in many fish's cases) bearing in mind fish managed to thrive without ever seeing daylight.

Just how much vitamin D does a frontosa produce at a depth of 100ft in its natural environment, how much does a cory sat at the bottom of the rio negro (30ft+ of black water) produce? For any animal to synthesize Vitamin D REQUIRES UVB radiation, A lot of the fish we keep dont get much of that where they swim, With our fish food being enriched with vitamin D already can fish survive without light indefinetely.

More importantly many breeders raise their fry in tanks without lights, all through their growing on stage they get no exposure to UVB light and manage to thrive and grow on dietry vitamin D.

Our normal aquarium bulbs do not produce amounts of UVB that are worth anything, the condensation tray particularly if its made of glass would block any of the small amounts produced by the bulb in the first place (most of which will already be blocked by the glass of the tube itself - UV specific lights require a special type of glass and phosphor to allow UV to pass) Once the small amount produced gets past the tube the condensation tray its then got to penetrate water, your fish will not be getting any appreciable amount of UV with which to synthesize vitamin D even with the lights on.

 

[three-fingers]

This whole thread has been a very interesting read so far. Threads with Bignose and andywg usually usually are, Davidtq has made some very interesting posts too recently and Tolaks input has also been very valuable.

Reading this raises a small possible issue for me. I don't like colour from 2 of the t8 tubes over my aquarium, and was planning on replacing them with reptile UV tubes (not decided which percentage), as I get a discount on them and I like the colour more - I had originally thought they would be do
I have no condensation tray between the surface of the water and my current tubes.

I know and have experienced with at least some plant species, when they are raised indoors behind glass and then put outside in unfiltered sunlight, they can die back. I've been told that this is because they receive no UV in the greenhouses, and when placed outside the UV kill them. This could be far off the truth, as there's tonnes of other factors that could effect the plants...

But I'm just slightly worried I could harm my fish using these bulbs, while on the other hand, I thought I would be doing them good by allowing them to synthesise their own vitamin D.

My surface dwellers (hatchet fish) come from the wild anyway, so have seen UV in their life, but not for years.
My tank bred fish on the other hand may not of, for example my angel fish might very well have been raised in a set up similar to Tolaks.

So is it possible I will have any problems or is the amount of UV penetrating the surface of the water going to be negligible anyway?
Nothing serious, and I'm probably being silly, but maybe someone has experience with tank bred fish being exposed to UV, or has read any papers that touch on the subject?

Anyway, keep going with this thread, it makes for a great read .

 

[Davidtq]

This whole thread has been a very interesting read so far. Threads with Bignose and andywg usually usually are, Davidtq has made some very interesting posts too recently and Tolaks input has also been very valuable.

Reading this raises a small possible issue for me. I don't like colour from 2 of the t8 tubes over my aquarium, and was planning on replacing them with reptile UV tubes (not decided which percentage), as I get a discount on them and I like the colour more - I had originally thought they would be do
I have no condensation tray between the surface of the water and my current tubes.

I know and have experienced with at least some plant species, when they are raised indoors behind glass and then put outside in unfiltered sunlight, they can die back. I've been told that this is because they receive no UV in the greenhouses, and when placed outside the UV kill them. This could be far off the truth, as there's tonnes of other factors that could effect the plants...

But I'm just slightly worried I could harm my fish using these bulbs, while on the other hand, I thought I would be doing them good by allowing them to synthesise their own vitamin D.

My surface dwellers (hatchet fish) come from the wild anyway, so have seen UV in their life, but not for years.
My tank bred fish on the other hand may not of, for example my angel fish might very well have been raised in a set up similar to Tolaks.

So is it possible I will have any problems or is the amount of UV penetrating the surface of the water going to be negligible anyway?
Nothing serious, and I'm probably being silly, but maybe someone has experience with tank bred fish being exposed to UV, or has read any papers that touch on the subject?

Anyway, keep going with this thread, it makes for a great read .

Do acitinic lights produce a blue enough light for you? they are definetely safe for use, if not a small strip of glass in front of the reptile light would act as a UV filter.

As for safety of UV light for fish well its known that too much UV radiation can be bad for most species, fish dont tend to "bask" like reptiles do, I simply do not know if the amount of UV radiation needed for a reptile is dangerous for a fish or the plants in a tank. Certainly humans dont do too well under UV tubes long term, despite the fact that some UV radiation can be beneficial.

I wouldnt say it would be necesarily guaranteed disaster to have UV tubes on a tank, but I wouldnt consider it "guaranteed safe" either, I would look at other options like the acitinics.

I really wouldnt be a fan of adding the lights thinking the UV dose would do them good, if they are already thriving with the current setup getting their requirements from their current lighting \ diet.

 

[three-fingers]

Hmm thanks, If I do go for a reptile tube, I'll probably go for just one and of a lower percentage. I never knew UV tubes could be bad for us over the long term, but it sounds realistic so I'll see if I can find anything on that before continuing .

As you say, my fish are doing fine, and if UV tubes had any significant health benefits on fish, they would probably be widely used by fish breeders.

I'm just being very picky about the lighting, I like to mix and match different bulbs, and have subdued lighting in the evening .

 

[Davidtq]

UV tubes are definetely not good news long term for people much the same as too much time in the sun.

http/www.who.int/mediacentre/factsheets/...7/en/index.html

 

[dillowpillow]

Are lights necesary, I've got an algae problem and am putting my lights on to a minimum. God knows what algae it is, i've posted on here about it but with minimum responses, so i'm gonna go for the trial and error route.

So, my first port of call is minimum light with a med (anti hair algae). Hair algae is self diagnosis.

My question is, does light affect the fish health wise.

No, you never need to have lights on unless you have live plants. It would be fine to leave the light off to try and kill algea. In fact, it would be best if you put a dark towel over your tank with the lights off for five days. Only take the towel off to feed. This will almost certainly get rid of the algea.

 

[three-fingers]

UV tubes are definetely not good news long term for people much the same as too much time in the sun.

http/www.who.int/mediacentre/factsheets/...7/en/index.html

However sunbeds comprise of loads of high wattage UV lamps in a enclosed space designed so we receive as much light as possible .
I had always thought that sunbeds were in general a no-no because they emitted unnatural levels of both UVA and UVB and in different ratios to the sun, and while not bad on their own, the fact that people abuse them and that they give you the maximum recommended exposure makes them a risk.

After some further research I feel that one single (maybe two if I'm still not happy ) UV tube will be safe. One tube has a much lower UVA/B output than the sun. There's apparently also people who believe the UV output to be insufficient for some reptiles (turtles and tortoises specifically). This may also mean that the advantages in relation to vitamin d synthesis are negligible though...

 

[CFC]

Only one of my tanks in the fishroom has any regular lighting and that is a planted tank where the plants require light to grow. The remainder of the tanks are lit only by the two energy saver bulbs that light the room, there are no windows and i switch on the tank lighting only when i am doing maintainance or viewing the fish. Many of the fish in the fish room have now been in there for over 18 months (when we bought the house) and i havent seen any signs of illness or noticable problems from lack of sunlight, infact many of the fish are growing at such alarming rates that i am having to rush completing my new fish house in order to get them into larger tanks.

With many species of tropical fish living in darkly coloured water or in jungle streams where direct sunlight is blocked by the tree canopy above or indeed just living at such depths that sunlight cannot penetrate (remember Amazon abyss where they tried to dive to the bottom and only got about 10 meters down before it was so dark they couldnt see their own hands) i honestly cant see that vitamin D sythesis from sunlight is a essential part of a fishes well being, they may well be able to synthesise vitamin D but probably dont actually have to for survival.

That said i do plan on lighting the new fish house with tubes that replicate natural sunlight and have a 2% UVB rating because i plan on releasing a couple of day geckos in there to keep the creepy crawlies down (they will also have a full strength UV basking lamp too before i get linched by any reptile keepers) so i will monitor the fish to see if there are any benfits from having good lighting.

 

[three-fingers]

That said i do plan on lighting the new fish house with tubes that replicate natural sunlight and have a 2% UVB rating because i plan on releasing a couple of day geckos in there to keep the creepy crawlies down (they will also have a full strength UV basking lamp too before i get linched by any reptile keepers) so i will monitor the fish to see if there are any benfits from having good lighting.

Every aspect of that sentence sounds fascinating!
I love day geckos, and from the stories I've heard of them getting loose, I can vouch that plan will work!