Snails on maxima clam identification (PMD Outbreak)

[Miami Reef]

Most of my maxima clams have PMD or some sort of disease.

During the freshwater dip, I saw many of these small snails. Another freshwater dip a week later showed the same snails.

It’s not pyramidal, but I wanted to know if these could be parasitic? They really seem to hang out on the clams.

@minus9

I had a major loss of my clam collection. Most have perished. I haven’t added a clam in several months, so I’m not sure why it’s happening, but I’ve been noticing lack of growth for a while.

 

[Cthulukelele]

To me they look like sun dial snails which are another parasitic clam eating snail type

 

[Cthulukelele]

They will also eat other snails

 

[Miami Reef]

To me they look like sun dial snails which are another parasitic clam eating snail type

I did some searching, and I found a thread that shows a picture very similar to mine: https://www.reef2reef.com/threads/sundial-snail.181703/

The majority identified it as collonista.

What do you think?

 

[Cthulukelele]

I did some searching, and I found a thread that shows a picture very similar to mine: https://www.reef2reef.com/threads/sundial-snail.181703/

The majority identified it as collonista.

What do you think?

Collonista snails and sundial snails can be hard to tell apart aside from the little stabby tail on the underside of the sundials when they aren't retracted.

Given the context of them all hanging out on the clam and not elsewhere is what had me leaning more sundial snail, but I hope they're collonista as those are beneficial algae eaters

 

[Cthulukelele]

They'd also give a nice and clean (if frustrating) explanation of your lost clams and current PMD

 

[Cthulukelele]

If they are sundials, they can be hard to get rid of/control without adding a fish that would be quite taxing on your cleanup crew like a melanarus wrasse

 

[Miami Reef]

It just doesn’t look like a sundial to me. Sundials have a distinctive pattern with ridges that look like corn kernels.

After googling, it looks like a colonista to me. Apparently sundials prefer zoanthids, but the Zoa I have is growing fast and happy.

I’m thinking it’s PMD. I took me a long time to realize something was wrong. I haven’t seen shell growth for a while and assumed something was wrong with the water. It’s only when I started losing clams back-to-back did I realize it was PMD.

 

[Cthulukelele]

It just doesn’t look like a sundial to me. Sundials have a distinctive pattern with ridges that look like corn kernels.

After googling, it looks like a colonista to me. Apparently sundials prefer zoanthids, but the Zoa I have is growing fast and happy.

I’m thinking it’s PMD. I took me a long time to realize something was wrong. I haven’t seen shell growth for a while and assumed something was wrong with the water. It’s only when I started losing clams back-to-back did I realize something was wrong.

You'll definitely be able to tell in person better than me!

 

[minus9]

Most of my maxima clams have PMD or some sort of disease.

During the freshwater dip, I saw many of these small snails. Another freshwater dip a week later showed the same snails.

It’s not pyramidal, but I wanted to know if these could be parasitic? They really seem to hang out on the clams.

@minus9

I had a major loss of my clam collection. Most have perished. I haven’t added a clam in several months, so I’m not sure why it’s happening, but I’ve been noticing lack of growth for a while.

Those are harmless collonista snails, think of them as miniature trochus. Sorry, been busy doing other things.

 

[minus9]

Also, if you're treating for pmd, I recommend that you place the clams in another system or QT separate from your main system for a while. But, if you're treating all of the clams you may be okay. This just eliminates the possibility of reinfection from any residual pathogen(s).

 

[ccole]

Those are harmless collonista snails, think of them as miniature trochus. Sorry, been busy doing other things.

I agree! I have those as well and they don’t seem to bother my clams.

Do you have a picture of the affected clams? Did you see any improvement/mantle extension after the dips?

 

[minus9]

Sundial snails are pretty distinctive and easy to separate from others. The operculum will have a protective covering in the shape of a cone and most other snails that we keep are completely devoid of an operculum.

 

[Miami Reef]

Also, if you're treating for pmd, I recommend that you place the clams in another system or QT separate from your main system for a while. But, if you're treating all of the clams you may be okay. This just eliminates the possibility of reinfection from any residual pathogen(s).

Thank you.

 

[OrionN]

Those are not parasitic snails but just eat algae on the shell of the clams. Sundials (which these are not) are pest of Zoos. They don’t prey on clams.
How are your calms today?

 

[CHSUB]

I have 4 clams that are doing great with lots of new growth, however last month 2 are showing less mantle and have several to a dozen collonista snails? on them. I’m now wondering if these snails are annoying the clam and possibly leading to PMD? J Sprung writes that aiptasia can annoy clams to death, maybe same with these snails? How did your issue come out?

 

[Miami Reef]

The snails in the first picture were not parasitic. I don’t have the pyramidal snails, either. I don’t have this issue anymore.

 

[minus9]

I have 4 clams that are doing great with lots of new growth, however last month 2 are showing less mantle and have several to a dozen collonista snails? on them. I’m now wondering if these snails are annoying the clam and possibly leading to PMD? J Sprung writes that aiptasia can annoy clams to death, maybe same with these snails? How did your issue come out?

Collonistas shouldn’t bother clams at all and they’re usually nocturnal. Any other changes in the tank? Lighting? Parameters? New fish?

 

[CHSUB]

Collonistas shouldn’t bother clams at all and they’re usually nocturnal. Any other changes in the tank? Lighting? Parameters? New fish?

I would agree about the snails, have read they are harmless. However, might be bothering clams causing it to retract its mantle, my guess?

 

[minus9]

I would agree about the snails, have read they are harmless. However, might be bothering clams causing it to retract its mantle, my guess?

Can you take some pics so we can see what’s going on? Use a filter or turn up your whites, blue LEDs mask the details, so we need a clear picture. Also, PMD isn’t caused by stress, it’s caused by a protozoan that’s passed by an infected clam to another. Collonistas usually stay hidden during the day and they would only be interested in algae, so unless algae growth is on the upper margins of the shell, they wouldn’t come in contact with the mantle. Pyramid snails on the other hand would be visible at the upper margins and you would notice a decline in shell growth, if not a complete stoppage altogether.
Regardless, we need to have a clear image of the clams in question. Don’t rule out fish bothering the clams either. I had to remove a clam recently because of an aiptasia eating filefish was going after the mantle. I’ve also lost clams to a rogue yellow tang, so there are a number of possible culprits here.