Lighting Requirements for Tridacnids

[ezcompany]

Hello everyone, this is the updated version of my previous “Lighting Requirements for Tridacnids” thread. I hope this one will answer 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 never ending help. Please read the entire post as the information is designed to support each other. (especially the Tridacna Crocea section)


Tridacnid Lighting Requirements:

Tridacna Crocea



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



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



These clams are much more forgiving in terms of light than the upper two tridacna species. Assuming they are not placed in a nano due to the size they can reach, 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.

Tridacna Gigas



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



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.

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.

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.

[a4twenty]

nicely done, love the illustrated version

thanks ez

[mbbuna]

looks good EZ

BTW those clams in the photos are all mine ill be expecting a check

[team2jndd]

deffinately needs to be stickied. Will deffinately help other hobbyists when chosing the right clam for their tank.

[ezcompany]

team2njdd, i cannot edit my post so i cannot post the maximum size.
i also need to check the book by J.F. but then again if I posted everything on his book, there would be no point in buying his book It really is a fantastic read. I will just say that Squamosas reach over 25 inches easily, Gigas reaching 30 inches + (in captivity), and deresas hover around 20 inches. Maximas will reach over 15 inches but seldom do so. Croceas stay small, maxing out before 10 inches usually.

[drummereef]

Very nice, ezcompany. This helped me out alot as I will be embarking on my 180 gallon journey. Hopefully I will have some crocea clams in the near future.

[JR719]

Thanks ez and mb. I'm going to have both 48" T-5's and 250 mh on the new tank. I'll be ready for any of them.

[55semireef]

Very nice thread. I say we should sticky this one for sure.

[leslie hempel]

very informative thank you...

[EQCM2B]

Very helpful, thanks alot.

[ezcompany]

here's a bump

[benray4fun]

Not so fast---> "what's the sticky on the new LED lighting system since they weren't mentioned"...

[fefo23]

Realy good info, but i have a question, I have a 30 gal which clam i beable to keep whith 150 metal hi

[ezcompany]

benray4fun: ultimately what is measures is par values. i believe that even though the LEDs don't shine as bright as metal halides, they claim to have equal or better par. it is still a new technology and i don't know enough to comment on it.

fefo23: how deep is your 30 gallon?

[fefo23]

It's 17" and i have 3" sand bed.

[benray4fun]

Originally posted by ezcompany
benray4fun: ultimately what is measures is par values. i believe that even though the LEDs don't shine as bright as metal halides, they claim to have equal or better par. it is still a new technology and i don't know enough to comment on it.

fefo23: how deep is your 30 gallon?

That's a very honest and respectful answer. You're also correct, the par is better..."here's a link to read up on them"

http://www.advancedaquarist.com/2006/8/review2

[ezcompany]

woops, my grammar was a little off there
I THINK what i meant was "ultimately what matters are par values". I would love to try a Solaris but too bad the prices aren't too realistic yet. I'm hoping the new Current LED lighting system will be better pricewise and maybe performancewise.

fefo23: as long as you are using a decent 14k or lower bulb, you should be fine. i think 20ks will be pushing it.

[fefo23]

I belive its 10k, so a maxima will be fine in my tank

[benray4fun]

Originally posted by ezcompany
woops, my grammar was a little off there
I THINK what i meant was "ultimately what matters are par values". I would love to try a Solaris but too bad the prices aren't too realistic yet. I'm hoping the new Current LED lighting system will be better pricewise and maybe performancewise.

You're right, the prices are up there, however, justified when you're aware of the technology and capabilities. They do everything, turn off/on with built in timers, ramp up/down with built in dimmers, adjustable intensity/ color, use 40% less electricity than 250 watt MH, but put out more par with no heat and best of all..."the lamps last over 10 years!"
They're unbelievable, you guys should really research them as they are
worth every penny...IMO

[ezcompany]

so i'm starting to assume you have one yourself?
can you post pics of your set up? oh with a clam of course

[ThaNgBOm321]

good heads up for people that are looking into clams.. ( im one of them .. .. 400 se is good... i gather.. lol ) but can you also explain how to properly identify each type?? all this info is no good if you dont know what you have or want..

TIA
YzGyz

ohh and MBBUNA....... you sicken me...!!!!!!

[ezcompany]

look at the picss above

j/k mbbuna is your man for that
its usually easy to tell by looking at the mantle pattern and coloration. squamosas and maximas generally have scutes in the side of their shells, while croceas are smooth because they bore into rock. the best way to id is to look at the bysall opening, and thats where mbbuna comes in

[mbbuna]

Originally posted by ThaNgBOm321


ohh and MBBUNA....... you sicken me...!!!!!!

i think you are talking about when i said all the clams were mine, that was a joke i was razing EZ because he couldn't remember where he found the photos.

this will help you id them.

http://www.reefkeeping.com/issues/20...ture/index.php

http://www.clamsdirect.com/forum/viewtopic.php?t=1994

[benray4fun]

Those are beautiful clams...

[ezcompany]

wait, someone actually thought the gigas and squamosa were in a tank?