My old man cactus is in trouble!
My old man catcus has been fine for over a year. Now it has been looking very thin - it's almost hour glass shaped! When I touched it, the needles were almost all gone and it feels hollow. The white hair also looks a bit brown towards the bottom. Would should I do?
It sounds like you may have a case of rot. Take a look here to see if that helps.
I think I lost one of these cacti in a similar way! Is this species hard to grow and prone to rot?