sick looking ZZ Plant - what's wrong?

I have a ZZ plant in a bathroom with no direct light (no windows). The leaves still look great but many stems now have brown stripes. The latest new stalk is still opening - bottom leaves are green but the top bunch are brown.
Too much water?
Not enough light?
Help!

 

Both. Repot and move to a sunnier location, and it should recover. ZZ plants are pretty tough.

 

OK- I'll repot and move to a sunnier location.
Is there any plant that would live in less light than a ZZ can handle?

 

Spathiphyllum; sansevieria; philodendron.

 

Hoya carnosa is ideal for bathrooms, too.