I had orange and yellow in a tank for over a year before they succumbed to what I suspect was a bacterial infection.
They don't like the brightest light, but tank placement should give them a lot of current, and should be somewhere where you can feed them with a turkey baster or pipette.
I fed mine live brine 2-3 times a week, and they were growing new polyps like crazy. I tried other foods, and the coral accepted them, but non-live foods would sink to the bottom instead of staying suspended in the water column where the coral could catch it, so it was kind of wasteful. I fed my biggest colony (size of a softball when opened) about a half an ounce of live brine each feeding, squirting several shrimps into each polyp with a turkey baster.
When you are shopping, look for polyps that are fat and look like an "outie" belly button. If they are skinny and bony, they may not have the strength to feed.
After you buy them, they won't open immediately. Just make sure they have strong current, put a little food in the evening, and they will come around. They normally open at night, but you can get them to open in the day if you feed them at a regular time. Also, they will open if they "smell" (or whatever sense a coral has) food in the water.