Crocea color fading

ToiletTank13

New member
Got a Crocea that had a lot of emerald green/blue. After a month or so now the green dusting is starting to fade out, presumeably due to high lighting and an increase in zooxanthellae.

Through your experience, is this color fading due to high lighting?

Current lighting in tank is 3 x 250W USHIO 10K & 2 x 160W Actinic 03.

The Crocea is directly underneath the middle lamp approx 18" under the acryllic centerbrace.

Is that too close? Or is it the USHIO's? Does anyone think the clam would be better off under a 20K or those new XM bulbs?
 
It sounds like it may not be getting enough light. 18" under a brace is not direct. Initial signs of shedding zooxanthallae will be bleaching usually noncentral. Are water parameters satisfactory?
Adam
 
There are two possible explanations as far as I can see.
The first is that it came from a place that had low light on the tank and the clam is adjusting to halides.
The other is that there is too little light. As ADS says, 18" and beneath a centre brace is far from high light.
Clams show a significantly reduced rate of response compared to corals so a month is probably about the time that you would expect to see either of these responses appearing. Unfortunately the two possibilities are opposite and so I would leave the clam for another 10 days or so, if it gets worse, I would move it to an area of higher light, if it improves (or stops becoming worse), I would leave it where it is.
 
Try moving the clam higher in the tank or somewhere else in the tank where there will be more light. Having the clam under the center brace does it no good. Better now than later otherwise unhappy clam=dead clam. ;)
 
The problem with moving to higher light now is that if the reason for the bleaching is because it was kept under low light for some time then got moved to relatively higher light, then you will just increase the rate of bleaching.
 
firechild said:
The problem with moving to higher light now is that if the reason for the bleaching is because it was kept under low light for some time then got moved to relatively higher light, then you will just increase the rate of bleaching.
I am under the impression that since the clam was under the center brace, doesn't that block out some light therefore causing the clam to bleach as a result of not getting enough light? Please correct me if I am wrong. I am still learning about clams.
 
Clams can bleach due to sudden changes in light intensity whether they be increases or decreases. Although the light it is under now would not be considered high, it is all relative to where it was before being moved to this tank.
 
Had problems with a reefcentral email clogging up my mail account!

Anyway, thanks for all the replies. The center brace I mentioned is actually the top of the tank. It's a Clarity Plus tank 135 with two lid cutouts. The clam is actually placed in the center of the tank where there isn't a cutout. The top of the tank is clear acryllic so I would expect that most of the light is hitting the clam. I keep the top clean and free from salt so it should be getting nearly full light from the bulb.

One thing I was going to ask, the color of the clam where the green is fading appears to be shading to the brown zooxanthellae color. Could this fading to brown be from the USHIO 10K spectrum? And could it be a reaction to too much light, as in overproducing zoox, causing the brown?

Or is the brown just bleaching?

The clam came from Reefermadness... dunno what lighting they use.
 
Also,

I just ordered some 250 XM mogul bulbs. I was thinking this was more of a reaction to high lighting and the white spectrum from the USHIOs.
 
firechild said:
Clams can bleach due to sudden changes in light intensity whether they be increases or decreases. Although the light it is under now would not be considered high, it is all relative to where it was before being moved to this tank.
Makes sense. Guess it can go either way. :p

Keep us updated on the clam.
 
ToiletTank13 said:
One thing I was going to ask, the color of the clam where the green is fading appears to be shading to the brown zooxanthellae color. Could this fading to brown be from the USHIO 10K spectrum? And could it be a reaction to too much light, as in overproducing zoox, causing the brown?

Or is the brown just bleaching?

Firstly, acrylic tops can cut about 20-30% of the light when they are perfectly clean and this increases if there is salt on the acrylic.

If it is just a colour change to brown from its original colour, it may just be a response to a change in light intensity or spectrum. Unlike corals, clams do not generally show increased brightness under a spectrum closer to what 20Ks produce and may look nicer under 6500K or 10K. If it is getting lighter, chances are it is bleaching slowly but if it is just getting browner it may be a change in production of accessory pigments or an increase in zooxanthellae populations.
 
color seems to be going from the green dusting to a brownish color. I was put to me elsewhere that this could be a protective response to increased lighting, if indeed it is an increase in zoox. My thinking of the different bulbs was that they should augment the appearance of the clam to start, and since they are somewhat dimmer on my ballast than the USHIO's, might it be possible that the clam would then lose some of it's zoox in order to allow more light to penetrate and thus more color return to the clam?

Knop's book is in the mail, but a question on the bleaching, if the color fades from bleaching can the clam be saved or is it doomed?

Thanks for all your responses and time taken.
 
This sounds more like inadequate light. Clams will fade or 'brown' under these circumstances. Clams do recover from bleaching d/t inadequate light as long as it is not longstanding. Adam
 
hmmm.... just measured at 14" directly under 250W UHSIO-SE bulb through 3/8" clear acryllic kept clean. That's not enough light for a clam? There has to be a way to acclimate Croceas to less light. I've seen countless pics posted here in the forums where people have the same setup with clams on the bottom of the tank or what appears to be darker tanks. Those clams must have been just thrown in before the pic or they haven't been in the tank long enough to die from inadequate light.

I dunno tho, I thought where the clam originally was placed was visually fairly blistering in terms of brilliance. Couldn't picture how a clam 8 or 10 feet down on a reef could get more.

Maybe water temp then was a prob? 83 at the end of the day, from 80.
 
still didn't get the book yet, but another question as to movement in the tank.

Moving the clam from 15" under a 250 10K to just under the water surface for a total of about 7 inches OK or too much to quick? Clam still has a fair amount of green coloration to it.
 
Back
Top