My neolamps go wild for them. I have never seen any ill effect, but I did read somewhere that they were not ideal for Tangs. The notion goes that the shrimp are raised in soft, low pH water and that for fish accustomed to hard, high pH water, consuming something with that much % of mass at such a different pH & hardness could lead to shock. Again, I've never seen any problems...to the contrary it seems to be a good spawning trigger food for me... but the pH and hardness explanation seemed reasonable to me, so to be on the safe side I don't feed them very often anymore.