<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by MandarinFish:
<strong>Will a grouper munch a cleaner shrimp every time?</strong><hr></blockquote>
It's a tough call. There are 2 issues:
1) 9 times out of 10, the grouper will eat first and worry about species ID later. In other words, they may not plan to eat cleaner shrimp, but it's gone before they see what it is.
2) In the wild, the grouper probably doesn't see them that often. He knows where they hang out and goes there when he wants a cleaning. In the tank, they would be around all the time, so I'm not confident about how the shrimp would fare when they are right in front of him and the grouper is thinking "I don't need cleaning, but I am hungry..."
So it's theoretically possible to do, but it's very dependent on how you introduce the shrimp - shrimp first, grouper later would probably be better. And, I can't say that I've ever seen it done successfully in captivity.