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Lighting Requirements for Clams


ezcompany

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Update 8/13/13

Hello everyone, decided to drop by and start hitting this thread with minor updates as technology advances and new information have been made available.

 

I hope this will answer most of your questions in regards to providing your clam with the best lighting conditions possible. Most of the information here is based on personal experience and experiences shared by other fellow clam lovers. Supplemental information is credited to James Fatherree and his book, Giant Clams in the Sea and the Aquarium, and many thanks to Chris for his help. Please read the entire post as the information is designed to support each other. (especially the Tridacna Crocea section)

Please remember: Squamosas, Deresas and Gigas WILL outgrow your tank fairly quickly!


Tridacnid Lighting Requirements:

Tridacna Crocea

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These clams require the most light of the Tridacna family. They occur in the wild mostly in very clear waters less than 15 feet in depth. (6 meters according to J.F.) The minimum recommended lighting requirement for a healthy Crocea is under a 150 watt metal halide of a reliable 14k bulb at a maximum depth of 20 inches, preferably less. To be on the safer side, a 10k bulb is recommended, and is closer to the "true" color of natural sunlight. I have seen some Croceas under 70 watts of halide, but these are normally placed high up in the tank. 70 watt bulbs are also considered by some as the least developed bulb, therefore being more inefficient in terms of their output compared to their 150 watt counter parts. 150 watts of (14k) metal halides would be the minimum “safe” amount of lighting. They will do even better under a 250 watt or 400 watt metal halide. If you are using 250 watts and above, you can place the Crocea even deeper in your tank, or even use 20k bulbs. If using T-5s, make sure the bulbs have individual parabolic reflectors on them, and the clam is placed at the upper half of your tank to be “safe”. Power Compacts will in a lot of cases NOT be adequate for Croceas.

In the case of T-5 lighting, remember only the 10k bulbs produce enough photo energy for PAR on clams, and the actinics produce little to no PAR depending on color temperature. It is also noted that the longer the bulbs are, the more penetrating power they carry. Thus a Crocea should be fine in a 20 inch depth under a 36 inch fixture. Having a Crocea in a 20 inch depth under a 24 inch fixture raises doubts, as most 24 inch fixtures only have 4 T-5 bulbs under them, with 2 of them usually carrying heavy actinics or some shade of high color temperature bulbs. In this case a retrofit is recommended to be able to cram in more lower temperature bulbs.

Tridacna Maxima

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These clams require almost as much light as Croceas if not as much. In the wild they have a maximum depth of occurrence slightly deeper than Croceas, but are again mostly found in very clean and shallow waters. The best bet is to place them in the same lighting conditions as you would light a Crocea. The “safe” amount of lighting would be under a 100 watt metal halide if they existed, so I’m going to say 150 watt 14k metal halide under 20 inches or less as well.

Tridacna Squamosa

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Based on hobbyist experience, these clams are slightly more forgiving in terms of light than the upper two Tridacna species. In the wild however, they occur at the same depth T. Maximas do. This essentially means their lighting requirements are similar to Maximas, and should be treated as such. (with intense lighting) Assuming they are not placed in a nano due to the potential size they can reach, they will be happy under metal halides. There is no exact number for the wattage of the bulbs, but the “safe” amount of lighting would be anything more than 150 watts. I can no longer recommend Squamosas to power compact lighting, although I do know several clams that have been fine under them. (every clam is unique) T-5s are recommended over your regular power compact lighting, and a Squamosa will soak up Metal Halide lighting very happily.



Tridacna Gigas

Tridacna-gigas-red-wrasse-jj-0300-081609

Can suffice with even less amount of light compared to the Squamosa. They can thrive under most pc /vho combination, but again will be happier with lighting closer to that of its natural environment. Gigas can be found at depths up to 20 meters (J.F.) but some of the most successful aquarists have them under some type of metal halide lighting system and have recorded tremendous growth.

Tridacna Deresa

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These clams are probably the most forgiving in terms of light than the rest of the mentioned clams. Their maximum depth of occurrence is about 25 meters (J.F.), but like the Gigas, they will be much happier with the lighting requirement given to Squamosas.

Exceptions to the Rule

Many people claim that Croceas and Maximas can survive under power compact lighting. These cases are far and few between, but there are certain individuals that are able to tolerate lower lightings, at which most of their counterparts would not be able to survive. Nevertheless, you should not take the risk and hope to get lucky, it is better to be prepared to give them what they will surely thrive in. It is always good to provide at least enough light of the given species to thrive in, and NOT the bare minimum you think you can get by with. Plus, it is the least we can do for our animal, as well as our responsibility as hobbyist.

 

LEDs:

 

LEDs have successfully been implicated to SPS and clams. The information advertised by one specific manufacturer suggests a total power output of 70 watts and above for clams. There still remain concerns on whether LED bulbs are able to maintain their PAR outputs for over a year, as well as the wavelength of light it covers.


Light Acclimation

There is no artificial lighting stronger than the great ball of fire in our sky, so all clams can adjust to your lighting provided they are given proper acclimation. This is especially important to prevent light shock, and gives time for the natural population of the clam’s zooxanthellae to adapt to their new habitat and photo conditions. Acclimation can easily be done using egg crate screening, or other materials that cut/diffuse lighting intensity. Remember, switching from fluorescents to metal halides is a big change, and so is switching from 150 watts to 250 watts. Light switch from any system to LEDs must be done slowly and cautiously as some have reported bleaching of coral.

Bulb Life

Fluorescent light bulbs need to be changed about every 10 months as they lose their intensity from old age. For metal halides, people have reported that 20ks lose their intensity at 6 months, 14ks around 8-10 months, and 10ks almost one year. I have not seen solid evidence in regards to this matter, but personally would change my 14ks every 10 months. The best way is to see if your clam has any loss in zooxanthellae. Fading or less vibrancy in the mantle is usually an indicator of this.

I do not know the origin of the pictures as they were saved in my computer so I cannot credit them appropriately. The ORA photo of the Deresa is obviously credited to Ocean Reef and Aquariums. The sole purpose of this thread is for the benefit of everyone, so please understand I hope this thread has been helpful to all of you.

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Good readings Jin! B) My crocea is doing just fine under my 96W T5HOs. Granted I keep the clam in the upper half of the tank, and added individual reflectors to my daylight bulbs, so that helps out a bit. What I have noticed is that for my individual, it's really on the edge of lighting requirement in my tank. I say this because when salt residue starts accumulating on the splash guard of my light fixture, my clam tends to open up only slightly or maybe not even at all. A quick wipe down of the guard and the clam is happy again and fully opens. But I think it's adjusting well having gone from the 150w MH in your tank, to my 96w T5HO. For referance to others, my fixture is "24 and my tank depth total is "18. It's recommended that if you use T5 lighting for clams or even SPS, your bulbs should be at least as long as the tank depth or more preferably longer than the tank depth.

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The minimum recommended lighting requirement for a healthy Crocea is under a 150 watt metal halide of a reliable 14k bulb at a maximum depth of 20 inches, preferably less.

 

How did you determine this? What if I have 4-75w vho bulbs 2 inches above the tank? What if I have 2 40w NO fluorescent bulbs 3 inches above the clam?

 

Intensity (PAR in consideration of height) is more important than type of lighting.

 

In the case of T-5 lighting, remember only the 10k bulbs produce enough photo energy for PAR on clams, and the actinics produce little to no PAR depending on color temperature. It is also noted that the longer the bulbs are, the more penetrating power they carry.

 

Source? I don't know that I'd agree with either statement.

 

Thus a Crocea should be fine in a 20 inch depth under a 36 inch fixture. Having a Crocea in a 20 inch depth under a 24 inch fixture raises doubts, as most 24 inch fixtures only have 4 T-5 bulbs under them, with 2 of them usually carrying heavy actinics or some shade of high color temperature bulbs. In this case a retrofit is recommended to be able to cram in more lower temperature bulbs.

 

hmm...

 

Tridacna Maxima

 

The “safe” amount of lighting would be under a 100 watt metal halide if they existed, so I’m going to say 150 watt 14k metal halide under 20 inches or less as well.

 

hmm...

 

Tridacna Squamosa

 

they will be happy under metal halides of some sort, but will suffice with vhos, or even power compact lighting. There is no exact number for the wattage of the bulbs, but the “safe” amount of lighting would be anything above 100 watts of compact fluorescents in depths of less than 20 inches provided they are directly under the bulbs. T-5s are recommended over your regular power compact lighting, and a Squamosa will soak up Metal Halide lighting very happily.

 

You seem to have a bias for MH :)

 

Exceptions to the Rule

 

Many people claim that Croceas and Maximas can survive under power compact lighting. These cases are far and few between, but there are certain individuals that are able to tolerate lower lightings, at which most of their counterparts would not be able to survive. Nevertheless, you should not take the risk and hope to get lucky, it is better to be prepared to give them what they will surely thrive in. It is always good to provide at least enough light of the given species to thrive in, and NOT the bare minimum you think you can get by with. Plus, it is the least we can do for our animal, as well as our responsibility as hobbyist.

 

cool

 

Bulb Life

 

Fluorescent light bulbs need to be changed about every 10 months as they lose their intensity from old age. For metal halides, people have reported that 20ks lose their intensity at 6 months, 14ks around 8-10 months, and 10ks almost one year. I have not seen solid evidence in regards to this matter, but personally change my 14ks every 10 months.

 

I do not know the origin of the pictures as they were saved in my computer so I cannot credit them appropriately. The sole purpose of this thread is for the benefit of everyone, so please understand I hope this thread has been helpful to all of you.

 

What about other types of bulbs.

 

If you didn't notice I'm trying to encourage you to think outside of the metal halide box.

 

Why not tell people how they can do other types of lighting correctly rather than just push them towards thinking metal halide is the only way?

 

:)

  • Like 1
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i have little experience with keeping clams under fluorescent lighting.

i am sure they can be kept with a good combination of VHO, PC, or T5s without doubt. i am simply sharing the knowledge i have accumulated so far with others, and my bias towards Metal Halides is mainly due to the tremendous success of other hobbyist keeping them as well as myself. I have seen clams under T-5s transferred to Metal Halides and the coloration on the mantle compared to the previous lighting was like light and day. Again i am not saying other lighting options aren't viable, but Metal Halide is simply the easiest and most surefire way of keeping a happy clam.

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thanks eeeeze for sharing your extensive research and personal experience. that's a great start for a discussion on clams.

 

lgreen, if you've got something specific to add in favor of alternative lighting for clams (other than MH), please do share.

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thanks eeeeze for sharing your extensive research and personal experience. that's a great start for a discussion on clams.

 

lgreen, if you've got something specific to add in favor of alternative lighting for clams (other than MH), please do share.

 

 

i feel like cyclop eeeeeze

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lgreen, if you've got something specific to add in favor of alternative lighting for clams (other than MH), please do share.

 

I second that. I want to hear what specific knowledge/information/experience you have in keeping clams in lighting other than MH. As I'm sure others would like to hear as well.

 

 

EZ, good read and I would definitely ask for your opinion if I ever decide to get a clam. I've seen your specimens in person and they are beautiful, so I'm sure you are doing something right.

 

 

-Iz

Edited by Asin
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coral_addict
What type of clam(s) can I keep in my BC 14 with 72 watts of pc lighting?

 

A Cleaner clam! Just kidding. You should be able to keep a Crocea Clam until it reaches 3" and higher as it will require photosynthesis at that point for food rather then via feeding. Once it reaches 3" or bigger I would recommend you moving to MH. I have one in my BC14 with just 48 watts of PC lighting and it's beautiful and happy........for now at 2". It eats well and color is still nice. Personally I think once it gets larger than 3" it shouldn't be in a BC14 anyway. One more thing to consider is that your tank should be mature as I've tried to move my Clam to my BC29 with a Sunpod 150W and it didn't appear as happy in that water. Same temp and salinity but my BC14 has been running longer with more LS and LR compare to my BC29 which uses more Base rocks with regular sand. So now I moved my Crocea back to my BC14. I just ordered a Sunpod for my BC14 as well since I didn't want to take any chances but my LFS swear that he has a lot of friends who have successfully kept these larger Crocea clam for years starting at the same size as mine. He even show me pictures. I believe him but I was itching for a Sunpod so I bought it anyway. The only thing that I like about the close top is that I never needed to top off before a water change. But the MH SHIMMER effect made me forget about any hassle. I think at 72 Watts near the top, you should have a very good chance man. Try it out and let us know.

 

Shimmer on...........

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A Cleaner clam! Just kidding. You should be able to keep a Crocea Clam until it reaches 3" and higher as it will require photosynthesis at that point for food rather then via feeding. Once it reaches 3" or bigger I would recommend you moving to MH. I have one in my BC14 with just 48 watts of PC lighting and it's beautiful and happy........for now at 2". It eats well and color is still nice. Personally I think once it gets larger than 3" it shouldn't be in a BC14 anyway. One more thing to consider is that your tank should be mature as I've tried to move my Clam to my BC29 with a Sunpod 150W and it didn't appear as happy in that water. Same temp and salinity but my BC14 has been running longer with more LS and LR compare to my BC29 which uses more Base rocks with regular sand. So now I moved my Crocea back to my BC14. I just ordered a Sunpod for my BC14 as well since I didn't want to take any chances but my LFS swear that he has a lot of friends who have successfully kept these larger Crocea clam for years starting at the same size as mine. He even show me pictures. I believe him but I was itching for a Sunpod so I bought it anyway. The only thing that I like about the close top is that I never needed to top off before a water change. But the MH SHIMMER effect made me forget about any hassle. I think at 72 Watts near the top, you should have a very good chance man. Try it out and let us know.

 

Shimmer on...........

 

I disagree coral addict. Clams are able to create all their energy needs right from the beginning. The whole saying that a clam under 3 inches needs to be fed is a myth. within a month of the larval stage their mantles are fully developed and full of zoox, and can sustain them with intense lighting. heres a study where larval clams were kept in micro filtered water and not allowed to receive any particulate and they did just fine on light alone.

 

http://links.jstor.org/sici?sici=00...B2-N&size=LARGE

 

I personally do not think stock pc lighting will be enough for a crocea, but there are always exceptions to the rule. it is still best to provide them with light you are sure they will thrive in, instead of skimping by and wishing for the best. hope that helps

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Great, informative thread!

 

I am interested in adding a crocea to my tank. In your opinion/experience, how long should the tank be established (ie stable parameters) before I add it?

 

It is a 20 gallon with 150 watt MH.

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Great, informative thread!

 

I am interested in adding a crocea to my tank. In your opinion/experience, how long should the tank be established (ie stable parameters) before I add it?

 

It is a 20 gallon with 150 watt MH.

 

I would recommend your tank be at least a few months old with stabilized parameters before adding your first clam :) most people say 6 months to a year. with some care, you can get away with less.

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Coral Addict: thanks for the info :D

Ez: I upgraded the lighting from 48- 72 watts- what can I keep with that? I can put the clam within 3-4" of the light... what do you think?

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Coral Addict: thanks for the info :D

Ez: I upgraded the lighting from 48- 72 watts- what can I keep with that? I can put the clam within 3-4" of the light... what do you think?

 

i disagreed with coral addicts info above: "You should be able to keep a Crocea Clam until it reaches 3" and higher as it will require photosynthesis at that point for food rather then via feeding."

 

i still think 72 watts is a little iffy if you want me to be absolutely honest ;)

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Chupacabras

Have you read anything about Dr. Shimek changing his stance on the need to feed little clams due to thin mantles? I know Fatherree disputes the whole mantle-thickness argument quite fiercely in his book (which seems to agree with what Sprung and Delbeek say in The Reef Aquarium) but I would be interested in if there's been any retraction or modification of his view.

Edited by Chupacabras
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whats the flow requirement for a clam?? do they like alot, medium, or little flow???

 

i haven't read shimek's article sorry, but i've been told that James F. has reviewed all the limited information on Tridacnids and has come to his own conclusions. there is no doubt that almost EVERY creature found in tropical reefs benefit from plankton in some way, it is simply how the ecosystem is structured due to the water column, and I will definitely say clams will do better with supplemental feeding, but it is not necessary.

 

72 watts is very very low for a crocea or a maxima sorry!

 

flow requirements: clams are found where hard corals, soft corals are found, and can tolerate quite a bit of flow. there are no requirements, but i believe that a strong, indirect turbulent whorling type flow is always good. (which is pretty much almost impossible to recreate in nanos)

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