I've been to three different local Aquarium Stores and we're all stumped, so I'm hoping that someone here might have some advice!
I set up a 20L/5gal tank in Sept 2020, and the nitrogen cycle was complete in Novemberish. Other than the ramshorns I'm trying to keep, all I've got are two albino cories and some plants.
Since then, I've unsuccessfully tried to introduce 4 different lots of ramshorns from 3 different suppliers, but the same thing happens each time. They'll be okay for a couple of weeks, but then they'll start withdrawing into their shell and fade away and die.
After the first lot died, I went to the first Aquarium store and they said it might be a pH problem, as my tap water was 7.6. Since then, I've started using Aqua One pH down and an oxy shell to help supplement neutralising the pH.
I got the second and third lot from a different retailer, and the same thing happened. They were fine when I introduced them to the tank (stuck the breather bag in the tank to let the water come to temp, slowly acclimated them to the water conditions by adding a bit of water in at a time etc) and for a little while afterwards, then they just retracted into their shells and died.
I went to another Aquarium store for advice, and they said the ammonia was slightly elevated (the first shade of green after 0) but probably not high enough to be causing my problems. This is also where I got the 4th lot of snails from. They recommended I get a copper test done, even though I live in a brand new apartment complex that uses PVC
piping for the plumbing--just to make sure--but they didn't have that test, so I went to the third aquarium store.
They didn't detect any copper, and we tried to run through the possibilities:
I use a 30cm/12" T5 Fluro light, diamond quartz substrate, it has an Amazon Sword, an Anubia on driftwood, and some micranthemum tweedeii as "ground cover." I also have an air stone installed. The things I add to my tank are Aqua One conditioning salts, the pH down, an oxy shell, API root tabs, and Flourish Excel. I have a canister filter with coarse sponge, filter floss, carbon pad, and a ceramic noodle. I do a 20% water change every week by mixing the water in a bucket and testing to make sure it's pH neutral before slowly adding it in to the tank in front of the filter outlet. I replace the carbon pad every 2 weeks.
There's plenty of algae for them to eat on the tank, and they don't seem interested in the brine shrimps/bottom feeder pellets/algae wafers that I feed to my cories.
The latest thing I've been trying is to reduce the water temp. I was keeping it at the ambient temp of 25 degrees C/77F because various sites I've looked at said that ramshorns could take that temp, and that is also the temp that the second retailer was keeping theirs at.
A non-local friend of mine who is successfully keeping snails says he keeps his tank temp lower than that, so I slowly reduced the water temp to 22-23 degrees C/71-73F, and introduced the most recent batch of snails. They were doing really well up until the day before yesterday, when one of them started behaving differently. It stopped floating at the water surface like it used to and retracted into its shell on the gravel. It's still reactive for now, and its little tentacle stalk things are out, but it's behaving the way that the others did when they were on the way out. The other snail that I got at the same time is still going strong though.
Something that I've noticed is that before they start dying, they start developing white patches on their shells? Is that related? pic for example: https://media.discordapp.net/attachm...526&height=701
TL;DR: trying to keep ramshorn snails, they keep dying after a couple of weeks. No-one can tell why. I'm stumped, and really sad, because I really like snails and wanna keep some