Congratulations WK,
Once they settle and fill out you will see a lot of subtle colouration in these guys. The top male in my group shows quite a lot of red/violet through the rear of his dorsal and anal fins (along with shades of yellows/orange through the body). Not bad for a brown fish with blue stripes on the face!!!
For feeding > little and often (if possible), mine can get up to 5 feeds a day when I'm around the house, otherwise at least 2 feeds per day. I'm using frozen bloodworm, daphnia, brine shrimp and Promin granular food (fine). Don't worry abput the particle size, once they've picked off the food as it floats to the bottom, they'll then sift the substrate for what they've missed (a sand substrate is essential for these guys so they can naturally sift the substrate for food).
If they're reluctant to feed on frozen, use live daphnia (along with little bits of frozen) for 2 or 3 days. That should get them eating properly, allow you to move them on to frozen food and get rid of the sunken stomachs.
Along with the sand substrate, these guys demand high water quality standards (mine are in pH 5.6, GH 1, KH 0 and nitrates non detectable thanks to some fast growing floating plants), water changes run at a frequency of 1 to 2 times per week.
Good luck and keep us posted
Andrew