Requiem

Today I went to check on the hermit crabs and found Climber's empty shell upside down. Climber was curled upside down next to the plain water bowl, about 25cm away from its shell. Dead. There was a clear trail from its shell to its final resting place; it seemed as though it had tried to dig. Climber's corpse smellt strongly of chlorine. I suspect that it is a problem with the water. I'd noticed the smell recently every time I'd opened the lid, so I left the lid off during the day. Climber had also been strangely lethargic, looking like it was having difficulty moving about in its own shell.
I wish I had woken up earlier to check on them.
Looking at the abdomen, most of it was covered in a thin layer of yellow stuff, except for this one segment, which I suspect had come into contact with the sand.
I wonder what I did wrong. Climber was the smaller one, and by all rights should have survived for longer.
Farewell to one who brought much joy and smiles. An adventurous, curious little one, who should not have suffered in its last days. Irreplaceable. Thank you... may you rest in peace.