LIght Intensity (PAR) and Tridacna Clams

J1a

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Just give it plenty of light and make sure you see new shell growth underneath the mantle. Those changes are probably from a different spectrum of light or how the light is hitting the clam. Also, clams have the ability to move or change where the zooxanthellae reside in their mantles. Zooxanthellae aren't the only thing that produces pigment in the mantle.
I believe these are all true. However, it seems that while there are plenty of discussion on how acroporidae can "color up", there is little discussion on color morphing of clams.

If we can induce clams to develop higher contrast patterns, or to produce more iridophores, that would really be awesome. (At this stage, I think it's possible)
 

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I believe these are all true. However, it seems that while there are plenty of discussion on how acroporidae can "color up", there is little discussion on color morphing of clams.

If we can induce clams to develop higher contrast patterns, or to produce more iridophores, that would really be awesome. (At this stage, I think it's possible)
They won't change like corals change, but they may lean towards one color or another or those colors will darken or lighten with different light/spectrum, etc... They will establish their zooxanthellae density when they are extremely small, which goes unchanged for most of their lives, but as they age, they will actually lose some of the zooxanthellae. James Fatherree talks about this in his book.
 

J1a

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They won't change like corals change, but they may lean towards one color or another or those colors will darken or lighten with different light/spectrum, etc... They will establish their zooxanthellae density when they are extremely small, which goes unchanged for most of their lives, but as they age, they will actually lose some of the zooxanthellae. James Fatherree talks about this in his book.

It's not just about zooxanthelle (which is brown) when it comes to clam coloration, a main trait which we are looking for is the presence and arrangements of iridocytes.

These iridocytes help mitigate the impact of UV, and even change the wavelength so that it can be available for photosynthesis.


So. I don't think can write it off and say that clam color can't change.
 

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It's not just about zooxanthelle (which is brown) when it comes to clam coloration, a main trait which we are looking for is the presence and arrangements of iridocytes.

These iridocytes help mitigate the impact of UV, and even change the wavelength so that it can be available for photosynthesis.


So. I don't think can write it off and say that clam color can't change.
There’s also amino acids within the mantle tissue, combined with everything, the mantle can change in appearance depending on light angle, spectrum, etc.
It’s also completely random as well. They’ve conducted several studies where they fed clams zooxanthellae from other colorful clams to see if they would take on those colors and found that no change took place. They even conducted a study with different lighting sources, not all clams in the study changed color or appearance, but some did. So it’s possible that clams have the ability to change or at least create camouflage to reflect or absorb uv and other spectrums of light. But from what I’ve seen keeping clams and the books that I’ve read, it’s completely random and not all clams will change color. At least not in the same way that corals do. I watched my purple/gold maxima change, but it really was a subtle change. It seemed to darken up a little and get deeper colors, but also lost some contrast between the colors. Whereas before, there were distinct lines between the colors/pattern. So it’s completely possible that there can be color changes in the mantle, but it seems to be random at best. They are simply amazing animals and truly unique.
 

J1a

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There’s also amino acids within the mantle tissue, combined with everything, the mantle can change in appearance depending on light angle, spectrum, etc.
It’s also completely random as well. They’ve conducted several studies where they fed clams zooxanthellae from other colorful clams to see if they would take on those colors and found that no change took place. They even conducted a study with different lighting sources, not all clams in the study changed color or appearance, but some did. So it’s possible that clams have the ability to change or at least create camouflage to reflect or absorb uv and other spectrums of light. But from what I’ve seen keeping clams and the books that I’ve read, it’s completely random and not all clams will change color. At least not in the same way that corals do. I watched my purple/gold maxima change, but it really was a subtle change. It seemed to darken up a little and get deeper colors, but also lost some contrast between the colors. Whereas before, there were distinct lines between the colors/pattern. So it’s completely possible that there can be color changes in the mantle, but it seems to be random at best. They are simply amazing animals and truly unique.
I think I have read the article you mentioned here. I agree totally with you, tridacna are such amazing animals.

I'm really hoping as a community we can really have better understanding about tridacna physiology. Then perhaps we will have more targeted approach to show them in the best light (pun intended).
 

minus9

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I think I have read the article you mentioned here. I agree totally with you, tridacna are such amazing animals.

I'm really hoping as a community we can really have better understanding about tridacna physiology. Then perhaps we will have more targeted approach to show them in the best light (pun intended).
They look best under full spectrum day light. I’m setting up a shallow nano and thinking of using a Kessil Tuna sun instead of the tuna blue. 6500k does wonders with clams. My main tank I’m switching back to 14k halides and will have several species of clams.
 

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They look best under full spectrum day light. I’m setting up a shallow nano and thinking of using a Kessil Tuna sun instead of the tuna blue. 6500k does wonders with clams. My main tank I’m switching back to 14k halides and will have several species of clams.
A neutral light makes clam look good, certainly. But it probably offers less PUR compared to a bluer spectrum. So it's a balance imo.
 

oreo54

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They look best under full spectrum day light. I’m setting up a shallow nano and thinking of using a Kessil Tuna sun instead of the tuna blue. 6500k does wonders with clams. My main tank I’m switching back to 14k halides and will have several species of clams.
Hmmm...Kessils fw tunas lights generally lack color quality though it " might" depend on the generation.
Anyways with a " color" temp range of 6000- 9000-ish they will be low on warm wavelengths.
And a poor cyan output.
Since you like warmer(10-14000k) halides you may not be happy w/ the color rendition of the Kessils.

It is hard to be exact since kessil doesn' t release pertinent info.
I also have s suspicion that they changed their diode composition without any notice .

See graphs in post #2

360X is a completely different animal though.
 
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minus9

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Hmmm...Kessils fw tunas lights generally lack color quality though it " might" depend on the generation.
Anyways with a " color" temp range of 6000- 9000-ish they will be low on warm wavelengths.
And a poor cyan output.
Since you like warmer(10-14000k) halides you may not be happy w/ the color rendition of the Kessils.

It is hard to be exact since kessil doesn' t release pertinent info.
I also have s suspicion that they changed their diode composition without any notice .

See graphs in post #2

360X is a completely different animal though.
I will most likely use one of my extra 360x’s on the 10k setting or 100% color at first. But we’ll see?
 

vahegan

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Hi Dana, thanks for an interesting thread. A lot of good reading, I love those scientific articles that leak into the hobby.
I always assumed that Tridachna clams need as much light as possible, because they are mostly photosynthetic but, unlike SPS corals, have much more complex structure, including a heart and other organs to run, hence need to get much more of energy. Plus, my personal observation was that they like a bit of nitrate, say, 5-10ppm. That said, I never had success with small clams, but any larger than 3" were doing well.
 
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J1a

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I have added a squamosa clam to my aquarium one week ago. Within the week, the clam showed marked change in the contrast of the mantle.

PSX_20220114_173405.jpg


So perhaps Par and spectrum could change the look of a tridacna, to a certain extent.
I love clams. So here comes the week 2 update on that squamosa.

IMG_20220121_160440.jpg


The clam started to develop blue spots since last week (The red circled area, among others). The spots are hard to capture on camera, but it's obvious enough to see with my eyes. Hence for the photo the contrast is adjusted.

Another interesting observation is at the area near the edge of the mantle. There are pin sized area with extremely strong iridiance. The bright blue exceeds that of the Tahitian maxima clam. If you peer closely at the zoomed in photo, you should be able to spot it.

Let's see if there will be further development.
 

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This is dangerous, IMO. From all indications, light requirements are different for smaller and larger clams. Larger clams don't seem to need too much light, but the smaller ones all seem to do better with more. All of this said, they certainly can handle a bunch of light if you give it to them. 300 seems reasonable for most with maybe even a bit less for T. Deresa, but I don't want anybody to get the idea that they can raise a T. clam under 85 PAR... odds would likely be against you unless the clam was really large.

If anybody wants to see something crazy, google Gigas Clam Low Tide.

Honestly, this all makes so much sense to me. For 4 years, I had a Maxima.Clam grow from 6 "ridges" to 19 "ridges" to what looked like a 4x growth over that time.

All under 2 x Orbit Marine LEDs, and that's it! When I first started in the marine hobby, I had zero interest in SPS so my LFS recommended these lights.

But as I.became obsessed, I actually became upset when every expert told me these lights were sh1t and couldn't keep anything but softies and zoas. Upset with MY LFS for lying to me.

It NEVER made sense to me how maxima survived at 100-150 par on my 75g sandbed. Not only survived, but thrived. It wasn't until my 180g upgrade did it perish post move after its foot got damaged and it kept tipping over.
 
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J1a

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A little update. Two more week from post #31, the clam has shown even more changes.

IMG_20220209_185216.jpg


Although the blue iridescence did not increase, the mantle pattern takes on a higher contrast. The black patterns take on a more defined shape. Interestingly, some of these patterns started to develop white outlines, not unlike those from noae clam.
 

MartinM

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I have bright white new shell growth (about 1/4 inch) on blue squamosa's (3 to 5 inches in size) purchased this summer ranging from 300 to 650 PAR, with 8 or 9 hours of full daylight spectrum and 12 hours of total light.

6 t5's (3 blue plus, 1 coral plus, 1 actinic, 1 purpleplus), two kessil 360's, and 2 reefbrites, scheduled with ramp up and ramp down.

I feed live phyto daily (reef nutrition), once or twice, because i have xmas tree worms and nps coral in the tank too. I also feed oyster feast and some dried coral food, a few times a week.

My nitrates are high 20 to 40ppm and my phosphate ranges from 0.04 to 0.2.

Calcium and mag are normal to higher on the typical recommended range.

Ph ranges from 7.9 to 8.3, not everyday but fluctuates.

Alk is 8.5 to 9.5 typically

Interestingly my small maximas and small crocea's died.

Clams are cool, but i consider anything but deresa living a small miracle.

SPS, LPS, and softies and NPS all thrive. No weird coral deaths and nuisance algae, acros do well, tank on cruise control. It's a heavy in and heavy out system for sure.

I poked a clam to show growrh, lol.

20220102_223125.jpg


Screenshot_20220102-223436_Gallery.jpg
EditL: wrong reply!
 
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MartinM

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If your phosphate is really at 1.0, that could affect the zoox in the mantle. If not using a good tool like a Hannah, then I would not just guess. Microalgae, like dinoflagellates, are affected by high residual nitrate and phosphate levels, but at different levels for different kinds and sometimes the hosts can shield them a bit from super high levels.

I would kinda be shocked if it was really 1.0 if you have cyano... usually matting bacteria is growth-limited at this level, but who know and there are many different kinds.

T. Maxima do shift color a bit as they get larger... usually the same color, just not as intense. I am talking like at 75% of their max size.
IME the color intensity varies with lighting intensity. I’ve had even large (25cm+) maximas gain color intensity under more intense lighting (~3xx PAR to 4xx)
 
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MartinM

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The following are from my 25-year old notebook:
"Tridacna": 180 PPFD (PAR)
"Tridacna": 85
T. maxima: 160
T. maxima: 250
T. gigas: 120
T. gigas: 286 - Smithsonian tank. Clam was 10 years old.
T. gigas: 130
Hippopus hippopus: 400
These measurements were made in tanks from Baltimore to Seattle. Instrument was a Li-Cor quantum meter with submersible probe, calibrated for underwater readings. The question that arose in another thread was now to 'balance' light intensities to satisfy both Tridacna and Acropora. PPFD of 300 should be that balance.
I have a dozen maximas, croceas, and noae’s doing great, but all receive a minimum of 350 PAR. IME, growth stops below 300, and with clams, if growth has stopped, then they’re starving. Perhaps my measurements aren‘t as accurate, or, more likely, it varies by clams/conditions. A few clams thriving at low PAR doesn’t mean that most clams will thrive (or even survive) at low PAR. Your sample size is too small, and, as we all know, there are too many variables to make it possible to control for them all. FWIW, my sample size is also too small (12 clams), but I don’t want to risk them for the sale of seeing if they’ll thrive and/or survive at lower PAR than where they are now. IME, every time it dipped below 300, growth slowed to a crawl or stopped completely, regardless of the size/color of the clam.
 
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Dana Riddle

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I have a dozen maximas, croceas, and noae’s doing great, but all receive a minimum of 350 PAR. IME, growth stops below 300, and with clams, if growth has stopped, then they’re starving. Perhaps my measurements aren‘t as accurate, or, more likely, it varies by clams/conditions. A few clams thriving at low PAR doesn’t mean that most clams will thrive (or even survive) at low PAR. Your sample size is too small, and, as we all know, there are too many variables to make it possible to control for them all. FWIW, my sample size is also too small (12 clams), but I don’t want to risk them for the sale of seeing if they’ll thrive and/or survive at lower PAR than where they are now. IME, every time it dipped below 300, growth slowed to a crawl or stopped completely, regardless of the size/color of the clam.
The Smithsonian had a huge T. gigas at less than 300, and maintained it for 10 years. I agree that more light is likely better, and wish I had a better sample size. What meter are you using? Just curious.
 

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I’ll have to get the model #’s, my staff uses the newest Apogee model I believe, I personally use a decade-old apogee, but I’m currently at my winter home and away from my aquariums, I’ll try to get the info for you. I’m sure your measurements are more accurate than mine, though!

I think James Fatheree has a lot of measurements of various species from their natural habitats in his book, but it’s been several months since I read it, and I can’t remember what his sample size was. I remember the species were only found in narrow PAR ranges, however, with virtually no exceptions.

I‘ve also seen anecdotal evidence in my own aquariums of different color clams doing better/worse under different spectrums. I have a pinkish/gold maxima nearly touching a blue maxima, and the latter had slower growth under bluer light (was using the essentially purely blue Red Sea LED until I could get in a better, non-windexy light haha), presumably because more of the light was being reflected. So there could be variability with mantle color, spectrum, not to mention innumerable other factors!

I think, given the fact that it’s difficult to ‘over-light‘ intertidal clam species, it’s better to lean towards higher PAR rather than assuming lower can work because it has for a handful of individual clams. I feel the vast majority of hobbyists who have success with SPS but not with intertidal clams are losing their clams due to not enough PAR.
 
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Dana Riddle

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I’ll have to get the model #’s, my staff uses the newest Apogee model I believe, I personally use a decade-old apogee, but I’m currently at my winter home and away from my aquariums, I’ll try to get the info for you. I’m sure your measurements are more accurate than mine, though!

I think James Fatheree has a lot of measurements of various species from their natural habitats in his book, but it’s been several months since I read it, and I can’t remember what his sample size was. I remember the species were only found in narrow PAR ranges, however, with virtually no exceptions.

I‘ve also seen anecdotal evidence in my own aquariums of different color clams doing better/worse under different spectrums. I have a pinkish/gold maxima nearly touching a blue maxima, and the latter had slower growth under bluer light (was using the essentially purely blue Red Sea LED until I could get in a better, non-windexy light haha), presumably because more of the light was being reflected. So there could be variability with mantle color, spectrum, not to mention innumerable other factors!

I think, given the fact that it’s difficult to ‘over-light‘ intertidal clam species, it’s better to lean towards higher PAR rather than assuming lower can work because it has for a handful of individual clams. I feel the vast majority of hobbyists who have success with SPS but not with intertidal clams are losing their clams due to not enough PAR.
Thanks! I never did any work concerning compensation points, but I do know that the T. derasa showed no photoinhibition up to the limit of the light I had (1,600 PPFD). I ran across a thesis years later that confirmed this. Agreed - more light is probably better!
 

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