What is happening to my succulents?

[Siddharth Pawar]

Dear Friends,
Recently I have noticed that the leaves of Sedum are all falling suddenly without even tapping the plant. Also worth noticing is the appearance of fallen leaf. What surprise me is that the stem isn't showing any signs of rotting. Its planted it peat and gets watered once every 6-7 days receiving 7-8 cc water via metres cup.
Also the other succulent (I believe its Graptoverium) has suddenly started showing shrivelled leaves. It is planted in peat+perlite+sand mix and gets water every 7 days receiving around 10cc water.
Please help as to what can I do.
Thanks in anticipation.

[Steve Johnson]

You originally posted this in the Sick Cacti forum -- moved to the Succulent Growing Help forum, so you'll be more likely to get responses here.

[Shane]

I think the first plant isn't getting enough light

[Siddharth Pawar]

Hi Friends, finally I went ahead and unpotted the plant from it open terrarium pot to inspect the roots. The roots seem absolutely fine. No blackish discolouration, no worms. So presently its keep unplanted. I plan to keep it the same for another 3-4 days and observe over a period of time. But what about the lower 3 succulents?? Why are the leaves getting shrivelled?