Mine are very shy as well. I have three of them. I hardly ever see them. I actually forgot I had them until I saw this post. The last time I remember seeing them was about 2 weeks ago. They hide very well among my plants.

I don't think I have ever seen mine eat either.
They are now in water that has a ph of 6.2, KH 2, GH 3-4, temp of 26C and still remain shy.
Robert. (bobo31)