Cerith Snails, Cerithium sp.
2 introduced on the 10th November 2016. Another 2 added 13th May 2017 but one doesn't appear to have moved since so the total may already be down to 3. :o(
Update 30th Oct 2017: The Clibanarius antillensis hermit (was found to be wearing a new Cerith shell this morning, I think he must have killed to acquire his new home as the snail appeared to be alive and well the day before. I do have lots of spare shells but clearly they are not acceptable.
6 more Cerith snails added 31st May 2018.
Spotted one of the original Ceriths laying eggs on the glass on the 3rd July 2018. Sadly the eggs were all gone by the following morning.
Update 30th Oct 2017: The Clibanarius antillensis hermit (was found to be wearing a new Cerith shell this morning, I think he must have killed to acquire his new home as the snail appeared to be alive and well the day before. I do have lots of spare shells but clearly they are not acceptable.
6 more Cerith snails added 31st May 2018.
Spotted one of the original Ceriths laying eggs on the glass on the 3rd July 2018. Sadly the eggs were all gone by the following morning.