My cleaner shrimp died, had him for over a year. He was 75mm(3 inches) long - I know they're not expensive, but he was my friend... Fish in the system for quite some time now: cleaner wrasse, sixline wrasse, fire goby, midas blenny, algae blenny, coral beauty, sailfin tang, tile fish, common clown, false grammar and 6 humbugs(hope it's right). Water parameters are excellent and temp constant at 26deg. He looked fine the previous day and still took a piece of prawn from my fingers. What could've caused this?