Is this clam bleaching?

[jeffbrig]

So what exactly is up with this clam?

We bought it back in February. It was sold as a maxima, but I think it's more likely a crocea. Here's what it looked like on 3/15 (side / overhead)

About six weeks ago, it started "bleaching" in the center. About a week ago, I moved him up from the bottom about 6". Still looks just as bad, if not worse. Here's a current picture:

The clam opens the same as when it was new, and is VERY responsive to fish swimming over, or me working in the tank.

Tank is 27" deep and lit by T5s and 250w MHs (short photoperiod on the MH). Water is 1.026sg, 420Ca, 9dKH, 0 amm, 0 nitrite, 0 nitrate, low phosphate (hard to judge salifert kit). pH tends to run on the low side, usually bottoms out near 7.9 overnight (adding a kalkwasser reactor to offset this). The tank has run with somewhat low Ca/Alk in the past, but I've taken steps to keep those level up recently. Tank is pretty stable, lightly stocked, and contents include RBTAs, LPS, SPS, etc.


For reference, here is another clam in the tank. This one is a maxima (the white blotches on this have been there since before I got it from a fellow reefer, so I considered them to be normal). No issues with this one.

And 2 new baby maximas:

So, what's up with the first clam? Not enough light? Too much light? Low pH? Disease? Or just doesn't like me? My next move would probably be to put him in a less well lit area of the tank, and see if there is any improvement.

Any suggestions are welcome.

 

[383camaro]

You've probably already did this, but, have you checked for pyramidal snails? One of our clams did the same thing. I moved it around and noticed them on the bottom. I cleaned them off and the clam is recovering.

 

[hot4teacher]

Tagging along. I've got a crocea and a maxima what I thought was doing the same thing. The centers were 'bleaching' but there has been a lot of mantle growth over the last 3 months.

Dana

 

[jeffbrig]

No evidence of snails on the clam. I moved him down and away from the lights this weekend. We'll see if that makes any difference....

 

[deepbelow]

do you run any kind of phosphate removers or carbon or any other kind of removers. what type of skimmer are you using?? just out of curiosity how short of a photo period are you running??

B

 

[jeffbrig]

I run carbon, changed every month or so. No phosphate removers used, very little shows up on the salifert po4 test.

The skimmer is a recirculating ER RC500 (oversized for this tank). Water clarity is very good, so say others who have viewed my tank.

T5s are my primary lighting, 2 60" aquablue, 2 60" blue+ in SLS single bulb reflectors. These lights are slightly overdriven (100w each) on icecap ballasts for approx. 13 hours each day.

MHs come on for a couple of hours each evening for prime viewing. I'm not convinced that they're needed any more than this. Other light loving organisms in the tank are doing great - my remaining clams, RBTAs, a few acros, etc. When I've experimented with longer MH photoperiods, the coralline on my rocks bleaches and recedes from the exposed surfaces.

 

[Serioussnaps]

predation from other corals(RBTA's or LPS)/allelopathy?????

expelling zooxanthellae from long photoperiod???

dont stress from moving too much.... leave it where it is for a while

 

[jeffbrig]

Nothing close enough to touch (tank is lightly populated still), but there is an RBTA and a sarcophyton (toadstool), each maybe a foot away. Would you try moving it further away?

BTW, moving the clam is trivial. It's connected to a larger piece of clam shell, sits in it like a bowl. Came that way when I bought it.

 

[Brock Fluharty]

Your baby maximas look exactly like mine! I only have 1, but they look exactly the same. I got him today from my LFS.

 

[Bebo77]

jeff did you change anything 6 weeks ago? maybe they dosing sch or additives, new creatures? When did you get the Maxima? has the Maxima shown signs of color improvement since being in your tank?

 

[jeffbrig]

The only change I've made is months is paying closer attention to maintaining Ca/Alk levels. Nothing new, just more regularly adding randy's 2-part.


The Maxima was purchased in April, and looks about the same as it did back then. Here's an overhead shot from the day we bought it:

The Crocea was purchased in March, just 1 month earlier.

 

[Bebo77]

jeff have you tried feeding phytoplanton?

 

[jeffbrig]

No, I've never dosed phyto. I'd like to avoid it too, as it can add phosphate. My understanding is that this clam's big enough that it shouldn't need supplemental feeding - just good light.

 

[Bebo77]

thats what i am thinking Jeff but i have read your thread and i know that its not your water quality or your husbandry.. i think you may just have a "sick clam" you can try feeding it to try and nurse it back... other than that i am at a loss..

 

[jeffbrig]

Gabriel, here's an interesting new observation. I was taking a look in the tank this morning, and stood on a stepladder right next to it. From above, the clam still has lots of color - more green than blue. It's just when viewed from the side or at a low angle, the outer skin color looks like it's washed away. It seems like there's color present deeper in the tissue, just not visible from the side.

I'll try to post a picture this evening....

Strange, eh?

 

[Bebo77]

lol one of my clams is like that.. when i bought it it was this beautiful green then i placed it almost eye level in the tank and before i noticed it.. it was this "whatever" blue color.. it has since anchored its self on the rock and is doing well. i can still see the green when i get on a step ladder and look at it from above but i learned my lesson, i now place all clams on the bottom of the tank so that they can be viewed straight on or from above...

 

[OrionN]

It seem that your clam is bleach only on the part that directly exposed to light. It may get too much light or get Ultra violet light. Check and see if your bulb is cracked. If not, lower the light level a little, or lower you clam to decrease light. Try feeding also. It will help the clam recover.

 

[jeffbrig]

Here's an updated top-down picture to illustrate what's going on with the clam. It's more than the normal "dull colors when viewed from the side". You can still make out the areas with eroded outer skin, but there's still color beneath in the lower tissues.

I am less worried as more time passes, because the overall health doesn't seem negatively affected, but I do wish I could stumble across whatever change might make the clam happy.



Orion, there are no problems with cracked bulbs or anything like that. T5s are all in good shape, and the MHs are DE's in proper pendants (w/glass uv shields).


And for clam-lovers out there, here's a recent top-down shot of my baby maximas. They're doing great, and I believe they've visibly grown since I added them.

 

[jmaneyapanda]

As per Knop's book, when a clam bleaches out it's zooxanthellae, it retained it's protective pigment to filter UV, so there will still be some color, but different. Again, not my observation, but from Knop's book.

 

[jeffbrig]

Thanks for the info, I have not read that book!

What is the chance that aging bulbs could shift their spectral output to an increase in UV output? My T5s have been running 12-14 hour photoperiod for about a year now. The conventional wisdom is that they are good for 18 months without a reduction in PAR, but I don't know if there's any spectral shift. I'll look into that.