Aha! I found it:
Feeding larvae is never a straightforward issue and never as easy as looking at the food alone. I have raised a good number of mandarins now on nothing but rotifers. Obviously, mortality rates are quite high, but it can be done.
From about 3/4 the way down this page:
Andy, Now I remember reading that,... I think I dismissed it because I looked at it pessimistically. But even if only one made it, I would be so excited and encouraged to press on!!
Ahh… I wish I had a work schedule that would allow me to take on such a hobby like that!!
I guess I have to live vicariously through others in this matter.