It's not a rear thing today. First it appeared in Japan.
Such plants (I think you have seen Gymnocalicium) may almostly have no
chlorophilus. So they can't take their food for growing from sun
(photosyntes). Red or yellow cactuses live like a mushroom or deprive (but
they are till now flower-plants). Cactuses don't have enough roots to take
all minerals they need to live. And we have to use another cactus that is
more stronger like a pump for red cactus.