Pest snails not growing large anymore

[Sgooosh]

back then, the bladder and ramshorn snails would grow to around a few cm long
now they only grow to 1 cm. it has been around 2 years
I've noticed that they all have white scarred shells
is there a supplement that will help them grow larger?
I found out that in new tanks with new sand they grow larger... maybe because of the minerals?

 

[Colin_T]

Have you added any new snails during the time you had them?
If not, they are probably suffering from inbreeding. They get smaller, their shells are weaker, and they don't produce as many babies. They do sometimes develop cool new patterns but eventually they die off due to lack of new bloodlines.

 

[GaryE]

The pitting in the shells suggest low minerals in the water. Since I moved here, previously tough snail shells have kept their regular colours, but are conveniently very very thin and fragile in my soft water. Larger individuals tend to have discolouration. In the one tank where I add hardness via seashells in the filter, the shells are slightly harder to crush (I am a snail disliker).

The water was equally soft in my previous house, but I'll take a guess there were differences in the minerals that gave the overall ppm.

You could add calcium, I guess. That depends on your fish.

 

[Sgooosh]

Have you added any new snails during the time you had them?
If not, they are probably suffering from inbreeding. They get smaller, their shells are weaker, and they don't produce as many babies. They do sometimes develop cool new patterns but eventually they die off due to lack of new bloodlines.

No, there was 2 nerites and one died of old age recently
however the ones outside in the pond and the ones in my new small tank are still growing large and they are from the same bloodline

The pitting in the shells suggest low minerals in the water. Since I moved here, previously tough snail shells have kept their regular colours, but are conveniently very very thin and fragile in my soft water. Larger individuals tend to have discolouration. In the one tank where I add hardness via seashells in the filter, the shells are slightly harder to crush (I am a snail disliker).

The water was equally soft in my previous house, but I'll take a guess there were differences in the minerals that gave the overall ppm.

You could add calcium, I guess. That depends on your fish.

hmm thats a good idea, I like snails and i just think they are kind of cute looking. Will crushed coral work as well? I only have collection seashells

 

[GaryE]

I imagine any source of calcium will help for their shells. I went to a beach not far from here and my kids (now grown up) brought me a bag of broken shells. I figure I'll run out after another 30 years or so.
I can't believe I'm writing something that may help my ancient nemesis the snail.