Blue Maxima Clam suddenly has a pale, discolored tint to parts of it

[CampAquarium]

We have a large blue maxima clam that has been growing and doing great for about 6 months now. A couple days ago, we noticed that its flesh has taken on a sort of "cloudy" tint, that ends abruptly, in a pretty straight line. The clam is still opening well, etc, but this discoloration hasn't gone away, and it's getting us worried! It doesn't appear to be a film or any sort of excretion on top of the flesh, it looks like the flesh itself has changed color... sort of dull, lighter, color where the black spots are less clear, sort of chalky-looking.

Does anyone have any ideas what could be causing this, and how we can help our clam recover?

Helpful context:
We did a 10% water change earlier in the day that we noticed this discoloration.
Our tank is 165 gallons total, 120 gallons display.
We recently decreased the white light in our spectrum to help weaken some hair algae up on top of the rocks that we've been removing. (Do clams need white light?)

Our params (these were from right before the water change):
Temp: 76.7
Salinity: 1.025
PH: 8.0 (it's been stable here for almost a year now and things have been fine)
Nitrates: 0.0
Phosphates: 0.03
Alkalinity: 9.5 (we are actively trying to bring this down to 8.5, hence the water change that day)
Magnesium: 1465
Calcium: 386

Photos:

 

[EgotisticObeseChihuahua]

Can I have an approximate size of the clam? Are you feeding phytoplankton? Maxima clams don't like the sand bed and needs lots of light, about as much as an acropora. Place them on a higher position in your tank so they can get more light, and if it is under 4-5 inches I would recommend dosing phytoplankton to your tank. ( Most juvenile clams can't get enough nutrients just form photosynthesis.)

 

[Mr. Mojo Rising]

Do you know the par level on the sand? Judging from the trachy on the sand, I guess its probably low. Maxima prefers to be on rocks rather than sand. They are normally placed on the highest rocks so they can get the strongest light. Should be 300-350+ par, more is better. It does like a minimal amount of flow.

 

[MoparMike97]

As mentioned above, likely lack of light, especially since you recently cut back on the white specturum. I'd try moving it up onto the rocks and see if it improves.

 

[CampAquarium]

Can I have an approximate size of the clam? Are you feeding phytoplankton? Maxima clams don't like the sand bed and needs lots of light, about as much as an acropora. Place them on a higher position in your tank so they can get more light, and if it is under 4-5 inches I would recommend dosing phytoplankton to your tank. ( Most juvenile clams can't get enough nutrients just form photosynthesis.)

The clam is about 5 inches, maybe a bit longer. Do you think phyto would still help? We are already dosing a small amount at night a couple days a week for our gorgonian. But would a clam need more/during the daytime? Also, does dosing phyto cause any change in tank nitrates, phosphates, alk, etc, that I would need to be aware of if we increase how much/how often we are adding?

And yes, it is on the sandbed. It's been there for 6 months and been totally happy and healthy, so I would be surprised if light is the sole issue here (though we will certainly take a look at our placement and light intensity options).

Would light and nutrients cause the relatively abrupt change in coloration that we saw? I initially assumed it could be from the short drop in temp the tank would have seen during/after the water change (we live in Colorado, so our newly-mixed water is always a bit chilly, but we do our best to move fast and get things heated up again ASAP). But now it's been a couple days and the clam's appearance has not improved.

 

[CampAquarium]

Do you know the par level on the sand? Judging from the trachy on the sand, I guess its probably low. Maxima prefers to be on rocks rather than sand. They are normally placed on the highest rocks so they can get the strongest light. Should be 300-350+ par, more is better. It does like a minimal amount of flow.

I'm not sure if our structure will allow for it to be moved up the rocks, but I will obviously take a look to see if we can make it work. What's confusing is mostly that this color change seemed to be very sudden, when it's been in this placement with consistent light intensity for months and been extremely happy, bright, and growing well.

Unfortunately I'm not sure of the exact par in this spot, but you're right... I can try to figure it out based on which corals are thriving around it.

 

[CampAquarium]

As mentioned above, likely lack of light, especially since you recently cut back on the white specturum. I'd try moving it up onto the rocks and see if it improves.

Do clams require white light? Or does decreasing white light decrease the intensity overall? The clam has been extremely happy in this spot for a long time, so trying to figure out what recent change could be upsetting it.

We cut back on the white in our spectrum because we were told that corals only reaaaally need blue light, so this algae control strategy of ours was mainly focused on them. The blue light intensity has not changed, but obviously this was a coral-and-algae focused strategy and didn't really consider our clams.

 

[exnisstech]

A clam can take months to starve to death. I killed several that I thought were doing good because they were opening then poof gone overnight. I bought a par meter and found out I had been starving them. They need light and a lot of it. If your trachy is happy under that lighting your clam likely is not. My derasa on the sand gets 300 par and my maxima on the rocks gets about 400. As stated a maxima should be placed on the rocks or at least on a rock that is sitting on the sand provided there is enough light on the bottom. JMO

 

[minus9]

Your clam seems fine to me, there's new shell growth, which is one of the most important things to monitor. Their mantles can and will most likely change over time. These changes can be from lighting, chemistry, bacterial issues, etc... If it's growing in the current spot, leave it be, but if you notice there's no new shell growth, then you'll need to provide more light. The clam looks healthy to me, but maybe set a piece of rock next to it so it can stand upright or provide a flat or concave rock for it to attach to. Being on the sand isn't an issue, as long as it's growing.
For the others who commented above, look at the mantle and new shell growth. This clam is growing and appears to be healthy by all accounts.

 

[CampAquarium]

A clam can take months to starve to death. I killed several that I thought were doing good because they were opening then poof gone overnight. I bought a par meter and found out I had been starving them. They need light and a lot of it. If your trachy is happy under that lighting your clam likely is not. My derasa on the sand gets 300 par and my maxima on the rocks gets about 400. As stated a maxima should be placed on the rocks or at least on a rock that is sitting on the sand provided there is enough light on the bottom. JMO

If we remedy the light, and maybe help it out by spot-feeding phyto every so often, can it recover? Or once they start struggling are they goners?

 

[exnisstech]

If we remedy the light, and maybe help it out by spot-feeding phyto every so often, can it recover? Or once they start struggling are they goners?

I'm not saying yours is a goner, sorry if I implied that. I was just speaking from my experience which is somewhat limited. The only sign I know of to tell if a clam is not doing well is the lack of new shell growth, the white band along the top edge.
I can't comment on the phyto. I have never dosed phyto. I watched a video of Dr Mac from pacific east aquaculture and he states clams do not need to be fed even when small. I know many people do feed phyto but Dr Macs experience is good enough for me. And my clams seem perfectly happy without it.

 

[MoparMike97]

Do clams require white light? Or does decreasing white light decrease the intensity overall? The clam has been extremely happy in this spot for a long time, so trying to figure out what recent change could be upsetting it.

We cut back on the white in our spectrum because we were told that corals only reaaaally need blue light, so this algae control strategy of ours was mainly focused on them. The blue light intensity has not changed, but obviously this was a coral-and-algae focused strategy and didn't really consider our clams.

Clams definitely appreciate full spectrum light IME, and yes, unless you bumped up the power on the blue channels when you cut back on the whites, the intensity definitely dropped and likely irritated the clam.

Most people associate bleaching with too much light, but I've seen numerous clams that bleached due to lack of light. Most recently, my LFS had a large maxima that was partially shaded by a montipora colony, when he moved the clam, the shaded portion had lost much of its color. It was fully recovered within a few weeks. I also remember seeing a post on here somewhere of some croceas that had been overgrown with Xenia and also exhibited a dramatic loss of mantle coloration due to lack of light.

Your clam definitely looks healthy, and there's no problem keeping maximas on the bottom of the tank as long as they are getting their lighting requirements met. Although, it probably would certainly appreciate a rock or some rubble to attach to as well.

 

[minus9]

If we remedy the light, and maybe help it out by spot-feeding phyto every so often, can it recover? Or once they start struggling are they goners?

Don't spot feed clams, they don't need to be fed anything directly. But do feed your whole tank phyto and the clam will take what it wants, but it gets most of its nitrogen through fish waste, food and pulling nitrate and ammonium directly from the water. CLAMS DO NOT NEED TO BE FED AT ANY SIZE! Just provide quality light and stable parameters and the clam will be fine. Don't change anything because of a slight color change of the mantle, unless there's damage or active bleaching.

 

[JGT]

^^^this.

 

[CampAquarium]

I'm not saying yours is a goner, sorry if I implied that. I was just speaking from my experience which is somewhat limited. The only sign I know of to tell if a clam is not doing well is the lack of new shell growth, the white band along the top edge.
I can't comment on the phyto. I have never dosed phyto. I watched a video of Dr Mac from pacific east aquaculture and he states clams do not need to be fed even when small. I know many people do feed phyto but Dr Macs experience is good enough for me. And my clams seem perfectly happy without it.

Understood, I didn't think you were saying that. I'm just anxious because I'm so attached to every single thing in our tank, and a few things have been looking a little funky lately!

 

[ArachnoJoozt]

I noticed a nitrate value of 0 in the opening post, also pretty low phosphate. This can't be helping. Next to the clam, what is the livestock of your aquarium?
Changing the light to more bleus may also be a issue, it is my understanding that especially blue clams benefit from more white light.
Good luck with your clam!

 

[CampAquarium]

I noticed a nitrate value of 0 in the opening post, also pretty low phosphate. This can't be helping. Next to the clam, what is the livestock of your aquarium?
Changing the light to more bleus may also be a issue, it is my understanding that especially blue clams benefit from more white light.
Good luck with your clam!

We did add the white light back in yesterday, so hopefully that helps over time. I appreciate you answering that question of mine!

Re Nitrate and Phosphate:
Yeah I wondered if that was part of it. I made another post yesterday about our nitrates; we've been struggling to bring them up without our alk spiking. Our tank is well stocked to the point where it's hard to list things out: we have 17 fish, a bunch of snails/hermit crabs/conchs, a sand-sifting starfish, a bubble tip anemone, a large euphilia garden, a zoa garden, several acros, several montis, several lobos, etc. The anemone and a few of the corals have looked a bit sad lately, so I do suspect that nutrients are an issue. It seems like no matter how much we feed, or how much NeoNitro we dose, the nitrates are just NOT coming up at all! It's been a real struggle.

 

[minus9]

How often are you feeding your fish? With that many fish, you should be fine unless you’re only feeding once a day? Regarding the light spectrum, all clams are found in shallow clear waters, so a full “daylight” spectrum is preferred, plus clams look better under natural lighting. Regarding hair algae, manual removal and herbivores do the trick, trying to change the lighting to reduce algae isn’t going to work long term. Algae is really good at life, you can’t control algae by reducing nutrients. The only reason algae doesn’t overtake reefs is the presence of herbivores, in home aquaria, you are one of the herbivores (manual removal).

We did add the white light back in yesterday, so hopefully that helps over time. I appreciate you answering that question of mine!

Re Nitrate and Phosphate:
Yeah I wondered if that was part of it. I made another post yesterday about our nitrates; we've been struggling to bring them up without our alk spiking. Our tank is well stocked to the point where it's hard to list things out: we have 17 fish, a bunch of snails/hermit crabs/conchs, a sand-sifting starfish, a bubble tip anemone, a large euphilia garden, a zoa garden, several acros, several montis, several lobos, etc. The anemone and a few of the corals have looked a bit sad lately, so I do suspect that nutrients are an issue. It seems like no matter how much we feed, or how much NeoNitro we dose, the nitrates are just NOT coming up at all! It's been a real struggle.