Cattleya iricolor help!

[Blevins Bute]

Hi, I bought my first two Cattlyas a month ago, C. walkeriana and C. iricolor. I have both on a South facing windowsill, potted in a mix of large bark pieces and sphagnum moss. The walkeriana has immediately put out two new roots and (I think) a new leaf. However, the iricolor looks as emaciated as when I got it it. The bulbs are shrivelled, the leaves themselves kinda "dimpled" (I'm sure there's a botanical word for this) and I'm.lost about what to do. Does it need more water, less water? How can I get these bulbs to fatten up?

Thanks in advance for any help.or tips.