My cleaner shrimp is grumpy....why?
 

Have a cleaner shrimp amongst about 16 fish in an LPS/SPS 150 gallon tank. he used to seem to be cleaning parasites and such off of the fish, but lately he is almost attacking the fish and being aggessive. Is there a reason for this behavior?

Do you spot feed it

Sometimes...
 

he is under an outcrop of corals, so can be tough to reach at times. Is he perhaps not being fed enough?

If you get it accustom to spot feeding with tongs or Baster it will come out when you feed.
I would guess its not fed enough