Help diagnosing issue with T.Maxima clam

[Tridacnid Enthusiast]

As the title says, I'm pretty sure something is up with my T. Maxima clam, but I'm having trouble figuring out what it is. I recently had my T. Crocea clam die overnight and I was unable to figure out why, so I want to ensure that doesn't happen again.

The main differences I've noticed over these past couple of weeks is the mantle seems to have small cuts in it, specifically on the side of the clan furthest from the tank. It also seems to be fully extending it's mantle a lot less frequently. It'll usually fully extend it for a couple hours during the day, but does sort a half extension for the remainder of the day (see photos).

Some general information about the tank. It's been running for about 6 months and I've had the Maxima clam for about 4 months. It's a reef tank with softies and LPS and the non coral inhabitants are blue legged hermit crabs, an arrow crab, two peppermint shrimp, a watchman goby, a flame tail blenny and bristle worms. Temperature is set to 79 degrees and my most recent water chems are the following: salinity is 35 ppt, Alk is around 8 dKH, Calcium is 440 ppm, Magnesium is 1290, Nitrates are 2ppm, phosphates are 0.4 ppm.

I'm very new to reefing and my clam means a lot to me, so any input or advice is very much appreciated!

 

[minus9]

You have a pretty young tank to keep clams, especially the most light demanding species. Most likely something is biting the mantle (crabs?), but the most important thing I would address is the lack of light you're not providing the clam(s). For clams that size you should see new shell growth at least a few mm high, meaning, there should be at least 3mm of new growth on the upper margin of the shell at all times. You should be providing 300-350+ micro moles for at least 8hrs a day of full spectrum lighting.
I would also recommend that you buy James Fatherree's new book on clams on Amazon, it's usually $36.

 

[Mr. Mojo Rising]

Your clam has recently stopped growing, you should always see a clear white line of new clam growth at the top of the clam shell. If you don't see new clam growth on the shell, you should be panicking to figure out why.

It seems to be placed low in the tank, off to the side by the glass probably where is the lowest par, this clam needs very strong lighting.

 

[Tridacnid Enthusiast]

You have a pretty young tank to keep clams, especially the most light demanding species. Most likely something is biting the mantle (crabs?), but the most important thing I would address is the lack of light you're not providing the clam(s). For clams that size you should see new shell growth at least a few mm high, meaning, there should be at least 3mm of new growth on the upper margin of the shell at all times. You should be providing 300-350+ micro moles for at least 8hrs a day of full spectrum lighting.
I would also recommend that you buy James Fatherree's new book on clams on Amazon, it's usually $36.

Thank you for your reply! I made quite a few changes yesterday that will hopefully help. Most importantly, I moved the clam higher in the tank and I adjusted my light schedule for 8 hours of full spectrum light. Additionally, I isolated all of my hermit crabs to see if that helps with the mantle tears. I was also paranoid about pinched mantle disease, so I did a freshwater dip just to b safe as well. Since it’s struggling to grow, I’m going to begin supplementing in some phytoplankton as well. Are there any good brands you recommend? I also appreciate the book recommendation, I just finished reading a Julien Sprung book which talked about clams a decent amount, but I did feel it was a tad bit outdated.

 

[Tridacnid Enthusiast]

Your clam has recently stopped growing, you should always see a clear white line of new clam growth at the top of the clam shell. If you don't see new clam growth on the shell, you should be panicking to figure out why.

It seems to be placed low in the tank, off to the side by the glass probably where is the lowest par, this clam needs very strong lighting.

Thank you for your reply! There is some growth on the shell, but admittedly it’s not much. I did end up moving the clam higher up in the tank and tuned my lighting schedule a bit to give it more light. I think I’m also going to start supplementing phytoplankton to help boost its growth rate, especially if it wasn’t getting enough light. Are there any good brands of phytoplankton you recommend?

 

[minus9]

Thank you for your reply! I made quite a few changes yesterday that will hopefully help. Most importantly, I moved the clam higher in the tank and I adjusted my light schedule for 8 hours of full spectrum light. Additionally, I isolated all of my hermit crabs to see if that helps with the mantle tears. I was also paranoid about pinched mantle disease, so I did a freshwater dip just to b safe as well. Since it’s struggling to grow, I’m going to begin supplementing in some phytoplankton as well. Are there any good brands you recommend? I also appreciate the book recommendation, I just finished reading a Julien Sprung book which talked about clams a decent amount, but I did feel it was a tad bit outdated.

Phyto can help a sick clam, but it's not going to help it grow and stay healthy long term. I use EasyBooster on all my tanks, but using it to "feed" the entire tank and not a particular animal. If you can rent or borrow a par meter, then you can better understand how much light you're providing your animals. You'll never have too much light for a clam (there are times when acclimating to new light where you can cause issues, but nothing I see happening with 99.9% of hobbyists), especially with our lighting. Also, doing a FW dip with a stressed clam can do some harm, so know for sure you're treating PMD before committing to a dip.
I believe James Fatherree is releasing a new book soon, so be on the lookout. I'll post in this section when it's released.

 

[Tridacnid Enthusiast]

Phyto can help a sick clam, but it's not going to help it grow and stay healthy long term. I use EasyBooster on all my tanks, but using it to "feed" the entire tank and not a particular animal. If you can rent or borrow a par meter, then you can better understand how much light you're providing your animals. You'll never have too much light for a clam (there are times when acclimating to new light where you can cause issues, but nothing I see happening with 99.9% of hobbyists), especially with our lighting. Also, doing a FW dip with a stressed clam can do some harm, so know for sure you're treating PMD before committing to a dip.
I believe James Fatherree is releasing a new book soon, so be on the lookout. I'll post in this section when it'

I only dipped the clam because I was paranoid and I’ve never actually seen anything picking at my clams, so I decided to dip just in case it was PMD instead. The clam began opening up pretty soon after the dip so I hope that’s a good sign. I’ll definitely look into getting a way to measure par as well as easy booster. Thank you for all of your help.

 

[OrionN]

IMO, something is taken chunks out of the mantle of the clam. This can be clearly see on the video.

 

[Tridacnid Enthusiast]

IMO, something is taken chunks out of the mantle of the clam. This can be clearly see on the video.

I agree, I did isolate my hermits as they’re the most likely suspects in my opinion. I’ve never seen anything else bothering the clam aside from the occasional shrimp walking over it. The hermits on the other hand would linger and cling onto the shell itself. Still never seen one of them picking at the actual mantle.

 

[Mr. Mojo Rising]

I agree, I did isolate my hermits as they’re the most likely suspects in my opinion. I’ve never seen anything else bothering the clam aside from the occasional shrimp walking over it. The hermits on the other hand would linger and cling onto the shell itself. Still never seen one of them picking at the actual mantle.

nah, the clam will just close, hermits are way too slow to bite a clam. It takes a quick fish to sneak up on the clam and quickly dart in to grab a quick bite before the clam shuts. (its actually impressive to see it)

The hermit is just picking at algae or something on the shell.

 

[Tridacnid Enthusiast]

nah, the clam will just close, hermits are way too slow to bite a clam. It takes a quick fish to sneak up on the clam and quickly dart in to grab a quick bite before the clam shuts. (its actually impressive to see it)

The hermit is just picking at algae or something on the shell.

Hmm, well the only fish I have are a watchman goby and a flame tail blenny. Both are pretty shy and just keep to themselves as far as I can tell.

 

[OrionN]

I never have a Flame tail blenny but have known other blenny to take bites off of clams.

 

[minus9]

Yeah, the blenny and arrow crab were high on my list of culprits. Arrow crabs are not reef safe.

 

[Tridacnid Enthusiast]

Yeah, the blenny and arrow crab were high on my list of culprits. Arrow crabs are not reef safe.

I have seen the blenny pick at a snail once, but my arrow crab doesn't really seem interested in any coral for the time being. I understand their temperament can vary quite a bit, but for the time being he's the least likely culprit from my observation.