snails shell question

[Patrice]

Hi, last year, I tried to add snail to my tank. unfortunatly, they all died. Before they died, i've notice holes on there shell.
I never try to push my observation more but, now that I want to give it an other try, I am looking for the cause of that.
could it was a Ca that was missing?

 

[Tom Barr]

No, shells decompose rapidly and dissolve, just like corals etc.
Even in Salt water...........and Ca++ levels at 400ppm............

Still think it's because of low Ca++ levels?

Living animals and algae use OH's to preciptate CaCO3 on to surfaces in definded patterns typically, once the animal/alga dies, this build up no longer occurs and the material is dissolved back into solution.

Freshwater snails, calms, mussles etc have a protective layer since they have a much larger gradinet than their salt counter parts.

If the layer is damaged for any reason, etc, then the shell will get "pitted" around the areas where the layer has been penatrated.


Regards,
Tom Barr

 

[Patrice]

So you meen that it beacause the shell has been damage that these holes apear? wow. is there a way to avoid this?

 

[Tom Barr]

Be nice to them

Algae that is attached, like BBA, will also do this if the BBa dies or is pulled off of them.

I do not think many hobbyists know much of the shells and how they are formed on mollusk.

It's a favorite test question when I taught Diversity form and function for Bio majors.

I do find it a bit odd there's never any talk about it on FW invert forums.
Although I'm probably not looking in the right spot?


Regards,
Tom barr

 

[Patrice]

well i think i should give it an other try. snails are cool. i dont remember having been rude with them. any way.

one think i realy hate about snails is that they climb on the glass. I like them when they just act like if there were no glass but i think i'll lose on that fight. this is also why I dont have plecos.

 

[dschmeh]

my pleco sucks on the snails and clams i think once the shells are damaged like tom says they start to dissolve the calcium in the shell goes from a higher concentration (the shell) to a lower one (the water) I havent tried adding calcium but have heard of people putting a little crushed coral in the filter . I belive this would be done to change water chemistry and not to help clams or snails.

 

[nursie]

Do you happen to know the calcuim content of your water? There are certain area here in the US that have problems with snails because of mineral content of the water.
People with low calcium in their water have added cuttlebone to their tanks for their snails to graze on. It's usualy something given birds to chew on for their diet. It will help some, but not entirely make up for lack of calcuim in the water column.

When you observe the live snails in your tank, do their shells show small holes or flakes? This may mean they are not getting enough calcuim either in water or diet.

 

[Patrice]

When you observe the live snails in your tank, do their shells show small holes or flakes? This may mean they are not getting enough calcuim either in water or diet.

I could be it. there is no mutch calcium in my water. maybe I should try to add something.




Thx

 

[reiverix]

I always have snail issues unless I dose Ca. Not just pitted shells, but the whole shell going white and brittle, ultimately causing death. I've tried on several occasions to go without dosing Ca but the end result is always the same. In my CO2 injected tank the effects are very quick (about a week) but take longer in non CO2 tanks.

 

[Tom Barr]

Several springs in FL have massive amounts of snails, at 25ppm CO2.

Some rare snails as well.

Regards,
Tom Barr

 

[reiverix]

Everyone I know here in Columbus has trouble with snail shell erosion. I've looked at the water report but there's nothing unusual. It's kind of annoying because I really like the critters in my tank. If I drop Ca, they start dying off. It would be a big coincidence that suddenly something damaged their shells everytime I lower Ca.

I'm open to suggestions. It would be a huge breakthrough to figure this out.

 

[nursie]

Don't you even have problems with them reproducing, Reiverix? Or are they just not living long enough to do that?

 

[reiverix]

I can keep a steady population if Ca is above ~60ppm. I've been thinking about some high calcium snail food recipes and see if that helps.

 

[Tom Barr]

Diet might be some of it.
But it's not precisely clear, CO2 is more likely the cause although many species seem unaffected in naturally high CO2 systems in nature.

Regards,
Tom Barr

 

[kangaroosoup]

I'm pretty sure it's a pH thing. Snail shells are composed of CaCO3 like everyone else said, which dissolves into the water at a low enough pH. When I started my tank, I aimed for the KH ~ 4 and pH ~6.8 to get a good CO2 level and my ramshorns' (which seem to be more sensitive than some other species) shells all started taking on a white pitted appearance. I've since taken to adding some baking soda during WCs to raise pH above 7 and still maintain a good CO2 level, and while the old holes in the shells haven't healed, new ones haven't developed either.

 

[Frolicsome_Flora]

A PH of lower than 7 can corode snail shells really fast. They really dont like acidic water. If your adding CO2 then its likely that your PH is going to drop below safe levels.

 

[VaughnH]

If I recall correctly, snail shells are not primarily calcium carbonate. They are, I think, mostly a protein. Most of us using CO2 with low KH have a pH below 7, without problems with snails, other than having far too many.

 

[Frolicsome_Flora]

If I recall correctly, snail shells are not primarily calcium carbonate. They are, I think, mostly a protein. Most of us using CO2 with low KH have a pH below 7, without problems with snails, other than having far too many.

Interesting, this is something that Ive read in 2 separate places now, both on snail/invert supplier website. Im wondering if theyre just over-covering their backsides?

 

[wiste]

snail shell composition

If I recall correctly, snail shells are not primarily calcium carbonate. They are, I think, mostly a protein.

That does not sound completely accurate.
My understanding is that the snail shell is primarily composed of calcium carbonate but that there is a protective outer covering.
The outer covering of the snail shell is the periostracum, which is mostly protein.
Drop the snail shell in acetic acid and the dissolving calcium carbonate will form bubbles of CO2 as it dissolves.

 

[Tom Barr]

That does not sound completely accurate.
My understanding is that the snail shell is primarily composed of calcium carbonate but that there is a protective outer covering.
The outer covering of the snail shell is the periostracum, which is mostly protein.
Drop the snail shell in acetic acid and the dissolving calcium carbonate will form bubbles of CO2 as it dissolves.

And you are correct........

All FW snails and mollusc possess a protective layer, this prevents dissolution in the much more corrosive FW waters.

Now there are plenty of snails in natural systems with high CO2 waters.......there are tons of snails, I do mean tons, in pH of 4.7-5.1 in Florida, you can see them all over.

So why do the snails in our tanks get them holes?

The only good hypothesis I've got is damage to the layer, fish, transport, algae holdfast(see BBA after the alga dies, it'll leave a nice hole).

There are a number of things that will harm the layer.........but the pH and CO2 of tank itself is not part of it near as anything in a natural system could ever suggest....

If you accept that pH and high CO2 do cause an issue, why doesn't harm the snails where they are from etc?
That's going to be a huge hurdle to accept that hypothesis.
I'll say that CO2 ferts and low pH once the layer is busted is not helpful, but they should not be the primary reason.

Olive nerites I've personally collected from Santa Fe river, the pH there is 5.0.
Other locations had CO2 levels of 25 ppm, and the entire substrate was covered in a dozen species of snail, clams, FW mussles etc.

The hardness was very low and in some places, very high.
Snails everywhere.

Regards,
Tom Barr