Ok. I have heard about them containing thiaminase, and I agree that they don't really have any nutritional value. I rarely use them, but I was just curious since I've never used them long enough to see any effects.They have tiasamain as well which can lead to neurological problems, parasites as well. They contain nothing as far as protien or nutrition. I do know this, I used to feed my cst goldfish and was advised not to, as soon as I quit feeding them he started growing really fast