Pinched mantle??

[NanoBoxes]

Need everyone’s opinion. First 2 pics are what my Derasa Clam used to always look like. 3rd is current. Would you consider this pinched mantle??
It’s been like this…not opening wide at all with mantle still out somewhat. Last year it hooked its shell on a nearby rock and closed hard snapping off a good size piece of shell. Would that have something to do with it?
it’s been in its current state for 4-5 months now.
Do you all recommend a freshwater dip? And if so, for what duration of time?

 

[SeaworthyAquatics]

Hard to tell from the pic. Does it look better in the morning than it does at the end of the day? Has it slowly gotten worse over the months? It will slowly spread across the mantle as the disease progresses. Has it grown any? Could be the issue with the shell breaking but I'd think it would have grown and healed it well enough by now if it isn't pinched mantle disease. I wouldn't do a FW dip until you're certain its PMD, but 30 mins with temp matched RODI, ph matched if you can. You'll also need a PMD free tank to put it in as PMD can spread through the water column.

 

[Dburr1014]

It looks like it's still attached correct? It looks like the mantle is actually ripped, has something been attacking it like a fish? What other animals are in the tank? Does it have any new growth! if you look under the mantle of should be pure white shell that would be new growth.

 

[minus9]

If it was pinch mantle, it would’ve been gone by now. Any aiptasia or vermitid snails on the shell? Also, that doesn’t look like a good spot for the clam. Flow and lighting change? Also, derasa, like other large clams will not use their byssal threads when they get to a certain size. They merely use their weight to keep them in place, that’s why they don’t have a large byssal opening. Also, what are your parameters? Lighting schedule it changes?

 

[Dburr1014]

Also, derasa, like other large clams will not use their byssal threads when they get to a certain size. They merely use their weight to keep them in place, that’s why they don’t have a large byssal opening.

Do you have anything to support this I have never heard this before

I do know they secrete mucus and actually melt the rock to sit in further.

Giant Clam Placement | Tropical Fish Hobbyist Magazine

Giant clams need intense lighting and excellent water quality. This article explains how to care for clams in the home aquarium.

www.tfhmagazine.com

 

[minus9]

Do you have anything to support this I have never heard this before

I do know they secrete mucus and actually melt the rock to sit in further.

Giant Clam Placement | Tropical Fish Hobbyist Magazine

Giant clams need intense lighting and excellent water quality. This article explains how to care for clams in the home aquarium.

www.tfhmagazine.com

Yes, the larger species use their weight to keep them in place as they get bigger. This is why they develop larger, heavy shells, which keeps them in place and upright. Crocea and maxima are boring clams (crocea more than maxima) and use a mild acid to melt the rock they are on. In the wild, you'll often find crocea's only showing the top part of their shells and the mantle extended, while the rest of the shell is buried in rock. Also, if you look at the bottom of the larger species of clams, you'll notice that their byssal opening is rather small and some (like hippopus) are almost nonexistent. Give me a second and I'll check out the link you posted.

 

[minus9]

Do you have anything to support this I have never heard this before

I do know they secrete mucus and actually melt the rock to sit in further.

Giant Clam Placement | Tropical Fish Hobbyist Magazine

Giant clams need intense lighting and excellent water quality. This article explains how to care for clams in the home aquarium.

www.tfhmagazine.com

Did you read the article you linked above? It actually gives you all the answers I posted.

 

[Dburr1014]

Did you read the article you linked above? It actually gives you all the answers I posted.

Lol, yes. I missed that part so I reread it. I guess I always thought they were always attached. At least someone learned something in the article I posted!

 

[minus9]

All good, that’s why we’re here, to learn. Btw, you can buy James Fatherree’s and Daniel Knop’s books on clams from Amazon used for a fraction of their original price. A lot of these books are unused or virtually brand new. There’s a wealth of information in these books (and most other books on the hobby). I think most new reefers overlook books because of the amount of info available on the web, but if it wasn’t for these books, that info wouldn’t exist. I’ve been doing this since the 80’s and I still reference books.

 

[skinz78]

Need everyone’s opinion. First 2 pics are what my Derasa Clam used to always look like. 3rd is current. Would you consider this pinched mantle??
It’s been like this…not opening wide at all with mantle still out somewhat. Last year it hooked its shell on a nearby rock and closed hard snapping off a good size piece of shell. Would that have something to do with it?
it’s been in its current state for 4-5 months now.
Do you all recommend a freshwater dip? And if so, for what duration of time?

Your clam look like something is picking on it, not pinched. What fish and inverts do you have in the aquarium?

 

[NanoBoxes]

Only three fish and an urchin and they never touch it

 

[skinz78]

That you see, which fish? No shrimp?

 

[Dburr1014]

Yeah, that looks ripped.
No crabs, shrimp?

 

[NanoBoxes]

Zero crabs or shrimp. Royal Gramma, Sixline, and a Cherub Angel. And I’ve had the Angel for over 3yrs, and watch the tank quite a bit. I’ve never seen the Angel nip at the clam.
my guess is after the large piece of shell got broken off it never grew back correctly and stressed it, irritating it. It never showed growth edges on its shell for past year. They are so dang sensitive. I think I will hold off purchasing another clam for a long while!

 

[minus9]

Zero crabs or shrimp. Royal Gramma, Sixline, and a Cherub Angel. And I’ve had the Angel for over 3yrs, and watch the tank quite a bit. I’ve never seen the Angel nip at the clam.
my guess is after the large piece of shell got broken off it never grew back correctly and stressed it, irritating it. It never showed growth edges on its shell for past year. They are so dang sensitive. I think I will hold off purchasing another clam for a long while!

If there's no new shell growth, then it's not getting enough light. This is what concerned me about it's current position on the side of the tank. What's the par in that area? It's true the derasa are found in some deep water (relatively speaking) but they will slowly starve to death if not provided with enough light.

 

[minus9]

Also, derasa are pretty fast growing clams, so there should always be visible new shell growth. They usually grow inches in a single year, easily.

 

[skinz78]

I bet it is the angel, you may not see it happening but I'm sure it is. Can you cut a plastic bottle in half, fill it full of 1/4" holes for flow and place it over the clam as a shield to see what happens?

 

[minus9]

I bet it is the angel, you may not see it happening but I'm sure it is. Can you cut a plastic bottle in half, fill it full of 1/4" holes for flow and place it over the clam as a shield to see what happens?

Low light and centropyge angel are a bad combo. My yellow tang killed my purple/gold maxima and took a fair chunk from my blue maxima. I had to sit next to the tank for a while before I saw it go after the clam. Needless to say, the YT found a new home shortly after. Isolate one or the other and see what happens? Regardless, the clam needs more light and a better home or it won't survive for much longer.