Well, I'm right back to being confused. (That's ok, that's normal for me!) I read and I read, and here's what I learned:

--Rosy reds contain lots of fat and thiaminase.
--Rosy reds contain very little thiaminase.
--All minnows contain thiaminase.
--Only certain minnows contain thiaminase.
--All live-bearing fish are safe.
--Some live-bearing fish contain thiaminase.
--No mention anywhere I could find of a thiaminase/color relationship.
--All frozen fish contain thiaminase as the freezing process releases the minute amounts that all fish carry and allows it to destroy all the B1 in the fishes body.
--My head is befuddled and for tonite, I give up.

My theory right now is, variety, variety. And gut load all feeders as best you can with good quality feed and vitamin/minerals.