hmm
I have lost yumas of all sizes, hehehe. I'm only meant to keep ricordia I guess. My tank has perfect conditions and I've kept them in all areas (shady, hi light, low light, low flow, med flow) you name it and after a few weeks they just shrivel up. All my creatures are coral safe too so u got me.
I've had to satisfy myself with rare colors of sanctithomae mushrooms and pretend they're yumas. :p
Ricordia are very easy to keep and proly will even do well under pc's depending on the size of your tank.
I have found that when storing a whole bunch of ricordia in my 75 at one time they tend to get stressed out and I think its because that tank doesn't have a good skimmer on it. But I'm talking like 20+ 5x4" ricordia rocks. Other corals in the tank also tend to get stressed out when I have lots of ricordia in one tank, so I think they must put out quite a bit of toxins compared to other corals.
Other than that, I've never had any problems with them. They will do well in high - med light, high - low flow, it doesn't really matter. Some morphs even prefer lower lighting to higher lighting. They come in a rainbow of colors, every time I think I've seen it all, then I find something crazy.
They grow fast, most of mine just get really fat instead of splitting. Here's my all time favorite one that I saved for my husband's personal collection.